To see the other types of publications on this topic, follow the link: Lectins; Cell-cell interaction; Immunoglobulin.
Journal articles on the topic 'Lectins; Cell-cell interaction; Immunoglobulin'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Lectins; Cell-cell interaction; Immunoglobulin.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Crocker, P. "Siglecs: sialic-acid-binding immunoglobulin-like lectins in cell–cell interactions and signalling." Current Opinion in Structural Biology 12, no. 5 (October 1, 2002): 609–15. http://dx.doi.org/10.1016/s0959-440x(02)00375-5.
Full text
2
Coppo, R., A. Amore, and D. Roccatello. "Dietary antigens and primary immunoglobulin A nephropathy." Journal of the American Society of Nephrology 2, no. 10 (April 1992): S173. http://dx.doi.org/10.1681/asn.v210s173.
Full textAbstract:
To investigate the role of dietary components in immunoglobulin A mesangial nephropathy (IgAGN), this study focused on gliadin, based on the reported association between coeliac disease and IgAGN as well as the pilot observation that a gluten-free diet was able to reduce the levels of circulating IgA immune complexes (IgAIC). IgA mesangial deposits in mice were induced by oral immunization with gliadin and in rats by inducing alcoholic liver cirrhosis, which increased the levels of IgA against dietary antigens (Ag). Gliadin was able to bind to cultured mesangial cells by a lectinic bond, which was reversed by competitive sugars. Binding increased mesangial cell tumor necrosis factor synthesis and decreased prostaglandin E2 production. Several gluten lectinic fractions modulate leukocyte oxidative metabolism, cytotoxicity, and chemotaxis. In IgAGN patients, serum IgA to dietary Ag were sporadically positive and IgAIC containing IgA to dietary components were significantly increased. The affinity of serum IgA to various lectins was increased in some patients. Conversely, no substantial deposition in renal tissue of dietary Ags was observed by immunofluorescence. A gluten-free diet, given to IgAGN patients with high levels of circulating IgAIC and positive antigliadin IgA, was followed by a decrease in the mean levels of both IgAIC and IgA to various dietary Ag, parallel to a reduction in proteinuria. These data suggest that dietary components, such as Ag or lectins, may play a role in IgAGN by promoting IgAIC formation and perhaps favoring mesangial localization via lectinic interactions.
3
Lakhtin, V. M., M. V. Lakhtin, A. Yu Mironov, V. A. Aleshkin, and S. S. Afanasiev. "LECTIN POPULATIONS OF NK CELLS AGAINST VIRUSES-ASSOCIATED TUMORS (REVIEW OF LITERATURE)." Russian Clinical Laboratory Diagnostics 64, no. 5 (October 7, 2019): 314–20. http://dx.doi.org/10.18821/0869-2084-2019-64-5-314-320.
Full textAbstract:
Analysis of the human NK (natural killers) cells and their functionally different populations in connection to tumor processes accompanied with viral infections is presented. Receptor lectins (non-immunoglobulin proteins and their complexes recognizing polysaccharides, glycoconjugates and glycopattern-containing molecules) play important role in regulation of innate immunity. Communicative diversity of NK-cell populations (in which lectins cofunction to other receptors) is directed against tumors and viruses. Effectiveness and selectivity of action of NK cell populations can be increased in cooperation together with adaptive immunity. Evaluations of occurrence, redistribution (also under influence of cytokines) and contribution of NK-populations (depending on lectin receptors recognition coupled to multifunctions of receptors) in respect of increasing antitumor and antiviral immune responces are given. The data indicate extended prospects of lectin receptors (coupled to other type receptors) containing NK populations of the network compartment of innate immunity upon realization of different variants of organism protection in cooperation with cellular and humoral immunity. Such NK populations are the basis for further intercellular interactions. Innate immunity Cross-Talk, involving the leader NK cell populations acting according to humoral immunity mechanisms, acts on duty regime (importance for therapy of chronic pathology) that results in providing optimal combined antitumor and antiviral cytokine and cytotoxic responses according to the principle of action as «network-in-network». The influence network of lectin, Ig-like, cytotoxic, other regulator NK populations (also throuph redistribution of production of cytokines by immunocompetent cells) is perspective for forming early prolongated antitumor and antiviral processes of different types in organism. It is of importance to consider CD diversity of receptor repertuar of lectin, Ig-like and other NK populations revealing different ontogenesis as well as to seach patient key NK-populations to select and construct personally (or for contingents in cases of epidemiological significance) optimal therapeutic/prophylactic NK populations (like variants of CAR-T). Aforementioned data indicate perspectiveness of NK cell populations in development of new antitumor/antiviral effective and selective vaccine strategies, preparations and regimes of their applications. Probiotic lectins reveal features of perspective ligands cofunctioning to network of NK cell populations.
4
Carlin, Aaron F., Amanda L. Lewis, Ajit Varki, and Victor Nizet. "Group B Streptococcal Capsular Sialic Acids Interact with Siglecs (Immunoglobulin-Like Lectins) on Human Leukocytes." Journal of Bacteriology 189, no. 4 (September 22, 2006): 1231–37. http://dx.doi.org/10.1128/jb.01155-06.
Full textAbstract:
ABSTRACT Group B Streptococcus (GBS) is classified into nine serotypes that vary in capsular polysaccharide (CPS) architecture but share in common the presence of a terminal sialic acid (Sia) residue. This position and linkage of GBS Sia closely resembles that of cell surface glycans found abundantly on human cells. CD33-related Siglecs (CD33rSiglecs) are a family of Sia-binding lectins expressed on host leukocytes that engage host Sia-capped glycans and send signals that dampen inflammatory gene activation. We hypothesized that GBS evolved to display CPS Sia as a form of molecular mimicry limiting the activation of an effective innate immune response. In this study, we applied a panel of immunologic and cell-based assays to demonstrate that GBS of several serotypes interacts in a Sia- and serotype-specific manner with certain human CD33rSiglecs, including hSiglec-9 and hSiglec-5 expressed on neutrophils and monocytes. Modification of GBS CPS Sia by O acetylation has recently been recognized, and we further show that the degree of O acetylation can markedly affect the interaction between GBS and hSiglec-5, -7, and -9. Thus, production of Sia-capped bacterial polysaccharide capsules that mimic human cell surface glycans in order to engage CD33rSiglecs may be an example of a previously unrecognized bacterial mechanism of leukocyte manipulation.
5
Gibbons, R. J., and I. Dankers. "Immunosorbent assay of interactions between human parotid immunoglobulin A and dietary lectins." Archives of Oral Biology 31, no. 7 (1986): 477–81. http://dx.doi.org/10.1016/0003-9969(86)90022-1.
Full text
6
Küppers, Ralf, and Freda K. Stevenson. "Critical influences on the pathogenesis of follicular lymphoma." Blood 131, no. 21 (May 24, 2018): 2297–306. http://dx.doi.org/10.1182/blood-2017-11-764365.
Full textAbstract:
Abstract The development of follicular lymphoma (FL) from a founder B cell with an upregulation of B-cell lymphoma 2 (BCL2), via the t(14;18) translocation, to a proliferating clone, poised to undergo further transformation to an aggressive lymphoma, illustrates the opportunistic Darwinian process of tumorigenesis. Protection against apoptosis allows an innocent cell to persist and divide, with dangerous accumulation of further mutational changes, commonly involving inactivation of chromatin-modifying genes. But this is not all. FL cells reflect normal B cells in relying on expression of surface immunoglobulin. In doing so, they add another supportive mechanism by exploiting the natural process of somatic hypermutation of the IGV genes. Positive selection of motifs for addition of glycan into the antigen-binding sites of virtually all cases, and the placement of unusual mannoses in those sites, reveals a posttranslational strategy to engage the microenvironment. A bridge between mannosylated surface immunoglobulin of FL cells and macrophage-expressed dendritic cell–specific ICAM-3–grabbing nonintegrin produces a persistent low-level signal that appears essential for life in the hostile germinal center. Early-stage FL therefore requires a triad of changes: protection from apoptosis, mutations in chromatin modifiers, and an ability to interact with lectin-expressing macrophages. These changes are common and persistent. Genetic/epigenetic analysis is providing important data but investigation of the posttranslational landscape is the next challenge. We have one glimpse of its operation via the influence of added glycan on the B-cell receptor of FL. The consequential interaction with environmental lectins illustrates how posttranslational modifications can be exploited by tumor cells, and could lead to new approaches to therapy.
7
Sokal, Izabela, Agata Kułacz, Wojciech Gorczyca, Maria Janusz, and Jozef Lisowski. "Guinea pig peritoneal macrophages. Differential effects of lectins on interaction with IgG immunoglobulins." Cell Biochemistry and Function 13, no. 1 (March 1995): 25–30. http://dx.doi.org/10.1002/cbf.290130107.
Full text
8
Odabashian, Mariette, Emanuela Carlotti, Shamzah Araf, Jessica Okosun, Filomena Spada, John G. Gribben, Francesco Forconi, Freda K. Stevenson, Mariarita Calaminici, and Sergey Krysov. "IGHV sequencing reveals acquired N-glycosylation sites as a clonal and stable event during follicular lymphoma evolution." Blood 135, no. 11 (March 12, 2020): 834–44. http://dx.doi.org/10.1182/blood.2019002279.
Full textAbstract:
Abstract Follicular lymphoma B cells undergo continuous somatic hypermutation (SHM) of their immunoglobulin variable region genes, generating a heterogeneous tumor population. SHM introduces DNA sequences encoding N-glycosylation sites asparagine-X-serine/threonine (N-gly sites) within the V-region that are rarely found in normal B-cell counterparts. Unique attached oligomannoses activate B-cell receptor signaling pathways after engagement with calcium-dependent lectins expressed by tissue macrophages. This novel interaction appears critical for tumor growth and survival. To elucidate the significance of N-gly site presence and loss during ongoing SHM, we tracked site behavior during tumor evolution and progression in a diverse group of patients through next-generation sequencing. A hierarchy of subclones was visualized through lineage trees based on SHM semblance between subclones and their discordance from the germline sequence. We observed conservation of N-gly sites in more than 96% of subclone populations within and across diagnostic, progression, and transformation events. Rare N-gly-negative subclones were lost or negligible from successive events, in contrast to N-gly-positive subclones, which could additionally migrate between anatomical sites. Ongoing SHM of the N-gly sites resulted in subclones with different amino acid compositions across disease events, yet the vast majority of resulting DNA sequences still encoded for an N-gly site. The selection and expansion of only N-gly-positive subclones is evidence of the tumor cells’ dependence on sites, despite the changing genomic complexity as the disease progresses. N-gly sites were gained in the earliest identified lymphoma cells, indicating they are an early and stable event of pathogenesis. Targeting the inferred mannose-lectin interaction holds therapeutic promise.
9
Rodrigues Mantuano, Natalia, Marina Natoli, Alfred Zippelius, and Heinz Läubli. "Tumor-associated carbohydrates and immunomodulatory lectins as targets for cancer immunotherapy." Journal for ImmunoTherapy of Cancer 8, no. 2 (October 2020): e001222. http://dx.doi.org/10.1136/jitc-2020-001222.
Full textAbstract:
During oncogenesis, tumor cells present specific carbohydrate chains that are new targets for cancer immunotherapy. Whereas these tumor-associated carbohydrates (TACA) can be targeted with antibodies and vaccination approaches, TACA including sialic acid-containing glycans are able to inhibit anticancer immune responses by engagement of immune receptors on leukocytes. A family of immune-modulating receptors are sialic acid-binding Siglec receptors that have been recently described to inhibit antitumor activity mediated by myeloid cells, natural killer cells and T cells. Other TACA-binding receptors including selectins have been linked to cancer progression. Recent studies have shown that glycan-lectin interactions can be targeted to improve cancer immunotherapy. For example, interactions between the immune checkpoint T cell immunoglobulin and mucin-domain containing-3 and the lectin galectin-9 are targeted in clinical trials. In addition, an antibody against the lectin Siglec-15 is being tested in an early clinical trial. In this review, we summarize the previous and current efforts to target TACA and to inhibit inhibitory immune receptors binding to TACA including the Siglec-sialoglycan axis.
10
Séïté, Jean-François, Divi Cornec, Yves Renaudineau, Pierre Youinou, Rizgar A. Mageed, and Sophie Hillion. "IVIg modulates BCR signaling through CD22 and promotes apoptosis in mature human B lymphocytes." Blood 116, no. 10 (September 9, 2010): 1698–704. http://dx.doi.org/10.1182/blood-2009-12-261461.
Full textAbstract:
Abstract Among various mechanisms for interactions with B cells, intravenous immunoglobulin (IVIg) may operate through the insertion of its Fc part into the Fc-γ receptor, or the binding of its sialic acid (SA)–bearing glycans to the negatively regulating CD22 lectin. It appeared that IVIg reduces B lymphocyte viability in a dose- and time-dependent manner. Furthermore, we show by confocal microscopy that SA-positive IgG, but not SA-negative IgG bind to CD22. This interaction reduces the strength of B-cell receptor–mediated signaling trough down-regulating tyrosine phosphorylation of Lyn and the B-cell linker proteins, and up-regulating phospholipase Cγ2 activation. This cascade resulted in a sustained activation of Erk 1/2 and arrest of the cell cycle at the G1 phase. These changes may be accounted for the efficacy of IVIg in autoimmune diseases.
11
Chiodin, Giorgia, Joel Allen, Philip J. Rock, Enrica Antonia Martino, Beatriz Valle Argos, Graham Packham, Patrick Duriez, et al. "Mannosylation of the Tumor Immunoglobulin Variable Region Informs Cell of Origin and Environmental Interactions in DLBCL Subsets." Blood 134, Supplement_1 (November 13, 2019): 1505. http://dx.doi.org/10.1182/blood-2019-127159.
Full textAbstract:
Diffuse large B-cell lymphomas (DLBCL) are a heterogeneous diagnostic entity of B-cell tumors whose behavior is variably influenced by genetic changes and environmental stimuli. They are usually divided into two major subgroups, the germinal center B-cell-like DLBCL (GCB-DLBCL) and the activated B-cell-like DLBCL (ABC-DLBCL), with different cells of origin and distinct clinical behavior. From a previous analysis of a small number of patients, we found that a fraction of DLBCL acquires N-glycosylation sites by somatic hypermutation of the tumor surface immunoglobulin (sIg) variable region, suggesting a connection with follicular lymphoma (FL). In FL, this leads to addition of mannosylated glycans in the antigen binding site (sIg-Mann), which allow interaction with microenvironmental lectins including dendritic cell-specific intercellular adhesion molecule 3 grabbing non-integrin (DC-SIGN). However, the distribution and the consequences of acquired N-glycosylation motifs in DLBCL was unknown. In this study, we investigated frequency, pattern and function of the mannosylated sIg in DLBCLs. DLBCL cell lines and primary samples were analyzed for the acquisition of the N-glycosylation motifs Asparagine-X-Serine/Threonine (N-x-S/T, where x ≠ Proline) in the tumor IGHV-D-J rearranged transcripts, and for binding to DC-SIGN by flow cytometry. HILIC-UPLC and crystallography were used to define structure of the glycans located in the sIg variable region. Interaction of sIg-Mann with DC-SIGN expressing cells was measured by flow cytometry and imaged by inverted fluorescence microscopy. Intracellular signaling was measured by Phosflow. Analysis of GCB-DLBCL and ABC-DLBCL cell lines and primary samples revealed that acquired N-glycosylation sites (AGS) were common in a subset of GCB-DLBCL (51%), especially in cases with a t(14;18) translocation (88%). Remarkably, the motifs were selectively acquired in the complementary-determining-regions (CDRs) of the tumor Ig (93%). In contrast, sites were infrequent in primary ABC-DLBCL (19%) and preferentially acquired in the framework regions (51% in all ABC-DLBCL cases, 88% in IGHV4-34 ABC-DLBCL). DLBCL cell lines with AGS which bound DC-SIGN had a t(14;18) translocation and were enriched with EZH2 and KMT2D mutations, while those without AGS, and unable to bind to DC-SIGN, were not. The sites acquired in the CDRs were permissive for addition of glycans terminating at high-mannose, as revealed by immunoblotting following EndoH treatment (that digests only glycans terminating at high-mannose) of the tumor sIg and by binding to soluble DC-SIGN. This was also confirmed by HILIC-UPLC and crystal structure of a sIg-Mann+ve lymphoma-derived recombinant Fab. Binding of DC-SIGN to sIg-Mann mediated an antigen-independent signal of lower levels than that mediated by anti-Ig, as measured by increased SYK phosphorylation in the tumor B cells. The sIg-Mann+ve GCB-DLBCL, but not sIg-Mann-ve DLBCL, formed clusters round DC-SIGN expressing cells. These interactions were inhibitable or disrupted by antibodies specifically targeting the DC-SIGN carbohydrate-recognition domain. Our results refine the phenotypic and functional characteristics of a GCB-DLBCL subset, in which the cell of origin has been selected to carry glycans terminating at high-mannose in the antigen-binding region. The acquisition of sites particularly in tumors harboring the t(14;18) translocation and mutations of epigenetic modifiers suggest a cell of origin common to FL, where these features occur early at transformation. Therefore, our data suggest the presence of a tumor cell ancestor with sIg glycans and genetic features common to FL and DLBCL. These results also document that those mannoses placed in the sIg variable region are functional and engage with DC-SIGN, to receive low level signals reminiscent of those protecting B cells from apoptosis. The possibility of inhibiting this antigen-independent interaction with anti-DC-SIGN antibodies in vitro suggests a potentially exploitable way for new therapeutic intervention. Disclosures Forconi: Menarini: Consultancy; Novartis: Honoraria; Janssen-Cilag: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; Roche: Honoraria; Gilead Sciences: Research Funding; Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau.
12
Stubbs, Haley E., Barbara A. Bensing, Izumi Yamakawa, Pankaj Sharma, Hai Yu, Xi Chen, Paul M. Sullam, and T. M. Iverson. "Tandem sialoglycan-binding modules in a Streptococcus sanguinis serine-rich repeat adhesin create target dependent avidity effects." Journal of Biological Chemistry 295, no. 43 (August 20, 2020): 14737–49. http://dx.doi.org/10.1074/jbc.ra120.014177.
Full textAbstract:
Sialic acid–binding immunoglobulin-like lectins (Siglec)–like domains of streptococcal serine-rich repeat (SRR) adhesins recognize sialylated glycans on human salivary, platelet, and plasma glycoproteins via a YTRY sequence motif. The SRR adhesin from Streptococcus sanguinis strain SK1 has tandem sialoglycan-binding domains and has previously been shown to bind sialoglycans with high affinity. However, both domains contain substitutions within the canonical YTRY motif, making it unclear how they interact with host receptors. To identify how the S. sanguinis strain SK1 SRR adhesin affects interactions with sialylated glycans and glycoproteins, we determined high-resolution crystal structures of the binding domains alone and with purified trisaccharides. These structural studies determined that the ligands still bind at the noncanonical binding motif, but with fewer hydrogen-bonding interactions to the protein than is observed in structures of other Siglec-like adhesins. Complementary biochemical studies identified that each of the two binding domains has a different selectivity profile. Interestingly, the binding of SK1 to platelets and plasma glycoproteins identified that the interaction to some host targets is dominated by the contribution of one binding domain, whereas the binding to other host receptors is mediated by both binding domains. These results provide insight into outstanding questions concerning the roles of tandem domains in targeting host receptors and suggest mechanisms for how pathogens can adapt to the availability of a range of related but nonidentical host receptors. They further suggest that the definition of the YTRY motif should be changed to ϕTRX, a more rigorous description of this sialic acid–recognition motif given recent findings.
13
Artemenkov, Alexey A. "Breach of ligand-receptor interaction in pathogenesis of disadaptive disorders and in pathology." Reviews on Clinical Pharmacology and Drug Therapy 17, no. 2 (August 9, 2019): 17–28. http://dx.doi.org/10.17816/rcf17217-28.
Full textAbstract:
The review summarizes information about the effects of ligand-receptor interaction in the normal state, during maladaptation and pathology. The mechanisms of changes in the functions of the receptors of the immune system that recognize pathogen patches, interact with immunoglobulins and participate in the immune response are shown. Data on interactions within the neurotransmitter systems of the brain are presented. The properties of lectins, follicle-stimulating hormone, progesterone derivatives and calcitonin are considered. The review also summarizes information on such cellular processes as cell growth, bone regeneration and remodeling, apoptosis. The role of thiazole retinoids in the regulation of cell differentiation and signaling pathways has been shown. Particular attention is paid to angiogenesis and vascular endothelial growth factor, receptors and ligands to fibroblast growth factor, galactins involved in oncotransformation processes. It was established that phosphatase with the Src2 homology domain (SHP2) is an important component of oncogenic signaling pathways. The mechanism of multivalent interaction of bacteria and viruses with the cells of the body is discussed. The interaction of nanoparticles (graphene, fullerenes) with biological objects is considered in sufficient detail. The article discusses the problem of receptor saturation and the activity of ex-orphan receptors that can act as targets for potential drugs. The prospects of creating new drugs based on π-cation interactions are shown. It was concluded that the study of the interaction of the substance and the receptor will allow to reveal the true mechanisms of dysregulatory pathology.
14
Schneider, Dunja, Hendrik Veelken, and Hassan Jumaa. "The Functional Role of Acquired N-Linked Glycosylation Sites On Follicular Lymphoma B Cell Antigen Receptors." Blood 120, no. 21 (November 16, 2012): 2704. http://dx.doi.org/10.1182/blood.v120.21.2704.2704.
Full textAbstract:
Abstract Abstract 2704 Follicular lymphoma (FL) is an indolent B-cell lymphoma characterized by apoptosis resistance due to overexpression of Bcl-2 as a consequence of the t(14;18) translocation, ongoing somatic hypermutation (SHM), and expression of B-cell receptors (BCR) with glycosylation of the antigen binding sites. Translocation and concomitant Bcl-2 overexpression can be found in healthy human blood B cells and is insufficient to drive lymphoma outgrowth in mouse models. Since most FL cells still express a surface B cell receptor (BCR) despite the disruption of one immunoglobulin heavy chain allele by the t(14;18) translocation, expression of an antigen receptor seems to be indispensable for FL development. Around 80% of FLs possess asparagine (N)-linked glycosylation sites (amino acid sequence: N-X-S/T) in their BCR variable regions that are not encoded in germ-line but are acquired through SHM. In contrast to germ-line-encoded glycosylation sites in the constant BCR region, where normal processing of the glycans results in termination on branched sugars like sialic acid, the variable region glycosylation sites carry mannose-terminating sugars. Recently, it has been shown that C-type lectins bind to and stimulate FL cells. Such lectins are normally expressed on cells of the innate immune system, e.g. dendritic cells (DCs), which also reside in close interaction with the transformed B cells in germinal centers. Importantly, previous studies point to an outstanding role of the tumor microenvironment in survival and proliferation of the FL cells. In this study, we demonstrate that the variable region glycosylation in FL BCRs contribute to stimulation of the cells as well as adhesion to cells of the innate immune system. The BCR from six FL and the appropriate glycosylation-defective controls in which the N-linked glycosylation sequons are removed by replacing the asparagine (N) residues with glutamine (Q) residues were expressed in the tko cellular reconstitution system. In tko cells, the BCR signaling cascade can be rendered functional at will through a tamoxifen-dependent mutant of the signal transducer SLP-65 (Meixlsperger et al., Immunity 2007; Dühren von Minden et al., Nature 2012). Tko cells expressing FL BCRs and their glycosylation-defective controls were tested for binding of a recombinant DC-SIGN/Fc fusion protein by flow cytometry. The mannosylated FL-derived BCR but not glycosylation-mutated receptors bound DC-SIGN. Stepwise mutation of individual glycosylation sites demonstrated variable contribution to the strength of lectin binding. Despite this specific binding to mannosylated FL BCRs, DC-SIGN/Fc failed to induce significant calcium mobilization of transduced tko cells. Crosslinking with anti-IgM, in contrast, led to a readily detectable BCR-mediated signal, thereby demonstrating functionality of the transduced BCR. To study the role of mannosylated FL receptors in interaction with their environment, we co-cultured cells expressing FL receptors containing or lacking N-linked glycans in the variable regions together with macrophages. Western blot analyses with a pan-phosphotyrosine antibody demonstrated higher global tyrosine phosphorylation in the lysates of cells expressing glycosylated receptors, thereby indicating a specific role for mannosylated V-regions in FL stimulation. Glycan-mediated interactions fulfill multiple important functions in the mammalian immune system including pathogen recognition and cell adhesion or trafficking. DC-SIGN serves as receptor for the uptake of mannosylated pathogens and contributes to cell-cell interaction by binding to the heavily glycosylated ICAM-2/3 (intracellular adhesion molecules-2/3). In the case of FL, it is therefore conceivable that DC-SIGN expressed on follicular DCs binds to the heavily mannosylated FL BCRs and serves thereby as adhesion molecule to keep the FL B cells within the follicular structure. We tested this hypothesis using live cell imaging on a DC sublayer and detected slightly slower movement and shorter tracks of cells expressing glycosylated FL BCRs as compared to control cells. Together, our results ascribe a role of the acquired glycosylation sites in FL BCRs for B-cell/DC interaction, thereby keeping the cells in the appropriate environment in a process that involves active signal transduction rather than triggering a classical antigen-induced BCR stimulation. Disclosures: No relevant conflicts of interest to declare.
15
YU, Zhenbao, Meryem MAOUI, Liangtang WU, Denis BANVILLE, and Shi-Hsiang SHEN. "mSiglec-E, a novel mouse CD33-related siglec (sialic acid-binding immunoglobulin-like lectin) that recruits Src homology 2 (SH2)-domain-containing protein tyrosine phosphatases SHP-1 and SHP-2." Biochemical Journal 353, no. 3 (January 25, 2001): 483–92. http://dx.doi.org/10.1042/bj3530483.
Full textAbstract:
The sialic acid-binding immunoglobulin-like lectins (siglecs) represent a recently defined distinct subset of the immunoglobulin superfamily. By using the Src homology 2 (SH2)-domain-containing protein tyrosine phosphatase SHP-1 as bait in a yeast two-hybrid screen, we have identified a new member of the mouse siglec family, mSiglec-E. The mSiglec-E cDNA encodes a protein of 467 amino acids that contains three extracellular immunoglobulin-like domains, a transmembrane region and a cytoplasmic tail bearing two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). mSiglec-E is highly expressed in mouse spleen, a tissue rich in leucocytes. The ITIMs of mSiglec-E can recruit SHP-1 and SHP-2, two inhibitory regulators of immunoreceptor signal transduction. This suggests that the function of mSiglec-E is probably an involvement in haematopoietic cells and the immune system as an inhibitory receptor. When expressed in COS-7 cells, mSiglec-E was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that mSiglec-E may function through cell–cell interactions. In comparison with the known members of the siglec family, mSiglec-E exhibits a high degree of sequence similarity to both human siglec-7 and siglec-9. The gene encoding mSiglec-E is localized in the same chromosome as that encoding mouse CD33. Phylogenetic analysis reveals that neither mouse mSiglec-E nor CD33 shows a clear relationship with any human siglecs so far identified.
16
Bono, Petri, Kristofer Rubin, Jonathan M. G. Higgins, and Richard O. Hynes. "Layilin, a Novel Integral Membrane Protein, Is a Hyaluronan Receptor." Molecular Biology of the Cell 12, no. 4 (April 2001): 891–900. http://dx.doi.org/10.1091/mbc.12.4.891.
Full textAbstract:
The actin cytoskeleton plays a significant role in changes of cell shape and motility, and interactions between the actin filaments and the cell membrane are crucial for a variety of cellular processes. Several adaptor proteins, including talin, maintain the cytoskeleton-membrane linkage by binding to integral membrane proteins and to the cytoskeleton. Layilin, a recently characterized transmembrane protein with homology to C-type lectins, is a membrane-binding site for talin in peripheral ruffles of spreading cells. To facilitate studies of layilin's function, we have generated a layilin-Fc fusion protein comprising the extracellular part of layilin joined to human immunoglobulin G heavy chain and used this chimera to identify layilin ligands. Here, we demonstrate that layilin-Fc fusion protein binds to hyaluronan immobilized to Sepharose. Microtiter plate-binding assays, coprecipitation experiments, and staining of sections predigested with different glycosaminoglycan-degrading enzymes and cell adhesion assays all revealed that layilin binds specifically to hyaluronan but not to other tested glycosaminoglycans. Layilin's ability to bind hyaluronan, a ubiquitous extracellular matrix component, reveals an interesting parallel between layilin and CD44, because both can bind to cytoskeleton-membrane linker proteins through their cytoplasmic domains and to hyaluronan through their extracellular domains. This parallelism suggests a role for layilin in cell adhesion and motility.
17
Alkhodair, K., H. Almhanna, J. McGetrick, S. Gedair, M. E. Gallagher, B. Fernandez-Fuertes, T. Tharmalingam, et al. "Siglec expression on the surface of human, bull and ram sperm." Reproduction 155, no. 4 (April 2018): 361–71. http://dx.doi.org/10.1530/rep-17-0475.
Full textAbstract:
Sialic acid (Sia) is a major constituent of both the sperm glycocalyx and female reproductive mucosal surface and is involved in regulating sperm migration, uterotubal reservoir formation and oocyte binding. Siglecs (sialic acid-binding immunoglobulin – like lectins) commonly found on immune cells, bind to Sia in a linkage- and sugar-specific manner and often mediate cell-to-cell interactions and signalling. Proteomic and transcriptomic analysis of human and bovine sperm have listed Siglecs, but to date, their presence and/or localisation on sperm has not been studied. Therefore, the aim of this study was to characterise the presence of Siglecs on the surface of bovine, human and ovine sperm using both immunostaining and Western blotting. Siglec 1, 2, 5, 6, 10 and 14 were identified and displayed both species- and regional-specific expression on sperm. Almost universal expression across Siglecs and species was evident in the sperm neck and midpiece region while variable expression among Siglecs, similar among species, was detected in the head and tail regions of the sperm. The possible role for these proteins on sperm is discussed.
18
Lee-Sundlov, Melissa M., Robert Burns, Renata Grozovsky, Silvia Giannini, Leonardo Rivadeneyra, Yongwei Zheng, Simon Glabere, et al. "Plasmacytoid Dendritic Cells Surveil Megakaryocyte Sialic Acid to Regulate Thrombopoiesis." Blood 136, Supplement 1 (November 5, 2020): 12–13. http://dx.doi.org/10.1182/blood-2020-142737.
Full textAbstract:
The Thomsen-Friedenreich antigen (TF-antigen) occurs during exposure of the underlying Core-1 disaccharide (Gal-beta(1,3)GalNAc) through the loss of its capping sialic acid (Sia). Exposure of the cryptic TF-antigen occurs during inflammation, during acute infections with influenza viruses or bacteria, in malignancies, and is associated with thrombocytopenia. Exposure of the TF-antigen on circulating blood cells, including platelets and red blood cells (RBC), can lead to severe thrombocytopenia or hemolysis in hemolytic uremic syndrome and other immune diseases. Recent data suggest that altered Sia may cause platelet destruction because treatment with the sialidase inhibitor Tamiflu increases platelet count in healthy and thrombocytopenic patients. In humans, genetic mutations involving Sia synthesis and transport, and atypical cell surface sialylation, unrelated to any genetic mutation, are associated with reduced platelet count, supporting the role of Sia in regulating platelet count. Immune cells, including classical dendritic cells (cDCs), plasmacytoid dendritic cells (pDCs), and subsets of T cells (CD8+, CD4+, and Treg cells) can also affect immune thrombocytopenia pathogenesis. Like many other immune cells, cDCs, and pDCs express Siglecs (sialic-acid-binding immunoglobulin-like lectins), which often contain immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that act as immunosuppressors. Whether BM immune cells monitor MKs via glycan-lectin receptors, including Siglecs and Sia interactions, to control platelet production is unclear. To investigate the role of the TF-antigen in thrombopoiesis, we generated St3gal1MK-KO mice (Pf4-Cre) that display increased TF-antigen specifically in megakaryocytes (MK) and platelets. St3gal1MK-KO mice developed significant thrombocytopenia, but had normal platelet half-life, suggesting that the TF-antigen affected BM thrombopoiesis. In vitro MK maturation and proplatelet production from primary ST3Gal1MK-KO mouse BM cells were also normal, pointing to extrinsic factors in the BM environment affecting thrombopoiesis. Platelet counts of St3gal1MK-KO mice were restored to wild-type levels by 1) crossing St3gal1MK-KO mice with Jak3KO mice that have impaired of lymphoid cell development, 2) by treatment with anti-inflammatory dexamethasone, and 3) treatment with a depleting anti-CD4 antibody. Immunofluorescence staining of the St3gal1MK-KO BM revealed proplatelet structures positive for GPIba+ and the TF-antigen, being infiltrated by mononuclear cells resembling lymphocytes. We speculated that immune cells surveil megakaryocytes to control thrombopoiesis. Bulk RNAseq of CD4+ cells in St3gal1MK-KO BM confirmed a population bias for Type I interferon (IFN-I)-releasing pDCs, a cell type regulated by unique sialic acid binding lectins (Siglecs). Inhibition of IFN-I activity, by a blocking receptor antibody improved platelet counts in St3gal1MK-KO mice. Co-cultures of pDCs with MKs show inhibited pro-platelet formation when TF-antigen is present on MKs with elevated IFN-I levels. Gene set enrichment analysis of BM pDCs single cell RNASeq (scRNAseq) data further confirmed that TF-antigen exposure by MKs up-regulates IFN-I transcripts. scRNAseq also reveals a new population of immune cells with pDC transcript signature and concomitant upregulation of immunoglobulin re-arrangement gene transcripts Igkc and Ighm. In conclusion, the data shows that recognition of aberrant MK sialylation by pDCs regulates thrombopoiesis through IFN-I secretion. Disclosures No relevant conflicts of interest to declare.
19
Hartnell, Adele, Jane Steel, Helen Turley, Margaret Jones, David G. Jackson, and Paul R. Crocker. "Characterization of human sialoadhesin, a sialic acid binding receptor expressed by resident and inflammatory macrophage populations." Blood 97, no. 1 (January 1, 2001): 288–96. http://dx.doi.org/10.1182/blood.v97.1.288.
Full textAbstract:
Abstract Sialoadhesin is a macrophage-restricted cellular interaction molecule and a prototypic member of the Siglec family of sialic acid binding immunoglobulin (Ig)-like lectins. So far, it has only been characterized in rodents. Here, we report the molecular cloning, binding properties, and expression pattern of human sialoadhesin. The predicted protein sequences of human and mouse sialoadhesin are about 72% identical, with the greatest similarity in the extracellular region, which comprises 17 Ig domains in both species. A recombinant protein consisting of the first 4 N-terminal domains of human sialoadhesin fused to the Fc region of human IgG1 mediated sialic acid–dependent binding with a specificity similar to its mouse counterpart, preferring sialic acid in the α2,3 glycosidic linkage over the α2,6 linkage. By flow cytometry with peripheral blood leukocytes, recombinant sialoadhesin bound strongly to granulocytes with intermediate binding to monocytes, natural killer cells, B cells, and a subset of CD8 T cells. Using antibodies raised to the recombinant protein, sialoadhesin was immunoprecipitated from the THP-1 human monocytic cell line as an approximate 200-kd glycoprotein. The expression pattern of human sialoadhesin was found to be similar to that of the mouse receptor, being absent from monocytes and other peripheral blood leukocytes, but expressed strongly by tissue macrophages in the spleen, lymph node, bone marrow, liver, colon, and lungs. High expression was also found on inflammatory macrophages present in affected tissues from patients with rheumatoid arthritis.
20
Odabashian, Mariette, Emanuela Carlotti, Shamzah Araf, Jessica Okosun, Francesco Forconi, Freda K. Stevenson, John G. Gribben, Maria Calaminici, and Sergey Krysov. "Immunoglobulin Variable Region Gene Sequences Reveal N-Glycosylation Motifs As an Early and Stable Event in Follicular Lymphoma Pathology." Blood 132, Supplement 1 (November 29, 2018): 4101. http://dx.doi.org/10.1182/blood-2018-99-112397.
Full textAbstract:
Abstract Introduction: Follicular lymphoma (FL) cells retain expression of a functional B cell receptor (BCR) despite the loss of one Ig allele due to the hallmark t14:18 translocation and ongoing somatic hypermutation (SHM) of the variable genes (V genes) which increases the likelihood of crippling mutations. SHM introduces N-glycosylation (N-gly) motifs within the V genes, a feature exclusively restricted to germinal centre (GC)-derived lymphomas. Oligosaccharides of the high mannose type are added to motifs and interact with calcium-dependent lectins associated with cells of the microenvironment. This activates the BCR signalling pathway and likely contributes to the survival, retention and proliferation of tumor cells in the GC. Determining at what stage of disease evolution N-gly motifs are acquired and their behaviour during progression can ascertain their importance in pathogenesis and their potential as an effective therapeutic target. To achieve this, we analysed motifs within the Ig heavy chain variable gene (IGHV) of tumor-related subclones across temporal FL samples. Method: Genomic DNA from three FL patients taken at different time points of disease progression were analysed. In total, 8 samples were selected, all carrying an IGHV3 rearranged tumor clone. IGHV DNA amplicons were sent for 2x250bp paired-end sequencing using the Miseq Illumina platform (Genewiz, NJ). Tumor-related reads with counts greater than ten were selected following analysis on IMGT/HIGH-V-QUEST. Reads were aligned and unique sequences were assigned as subclones. Additional tumor related reads sequenced on the Roche 454 Life Sciences Genome Sequencer FLX were available (Patients 4 & 5). Subclones were analysed for N-gly motifs and evolutionary pathways were generated using the IgTree program, based on intraclonal SHM profiles and homology of tumor clones to the germline IGHV sequence. Results: The earliest time point samples for Patient's 1, 3, 4 & 5 contained one N-gly site within the IGHV of the MC defined by the largest count number. These sites were conserved in >97% of unique subclones (p<0.0001) despite variations in the nucleotide sequence within the region as a result of ongoing SHM. This conservation included the most mutated subclones which had a mean SHM rate of 16.56%. Conservation was maintained across disease events. Patient 2 contained four N-gly sites located within the CDR1, FR2, CDR2, and FR3 regions. The first three sites were conserved in >97% of subclones in and across disease events, whereas the FR3 site was conserved in 95.5% of the diagnostic subclones and in ~80% of the relapsed and transformed populations. No subclones with loss of all four sites were detected for Patient 2. Patient 5 samples were taken from different anatomical sites with tumor populations acquiring distinct N-gly motifs, suggesting an early divergence in tumor evolution. Despite this, a minor population of motif positive clones are shared, suggesting a trafficking ability of subclones. Subclones with motifs made up ≥99% of the total tumor count, highlighting the motif as a feature of the tumor bulk, with motif negative clones representing a minor population. These negative clones are presumably lost during disease progression as they not shared between events. Evolutionary analysis revealed no additional sites are gained as motif positive clones expand while rare negative subclones cannot reacquire sites and do not undergo further diversification. Conclusion: We report for the first time that acquired N-gly motif sites are a clonal feature in FL disease as seen through their conservation both in the heterogeneous subclonal population and the overall tumor mass. The sites are also retained in progression-associated subclones while rare motif-negative subclones disappear. This suggests that although acquisition of additional driver mutations may dampen the tumor's microenvironment dependency, the motifs and added mannoses may retain functional significance at later stages of disease. The data indicates motifs as being a universal event of the reservoir cell pool responsible for propagating disease episodes. Targeting N-gly sites and their interacting partners may lead to the disruption of an early and vital FL-microenvironment interaction, presumably mediated through the mannose-lectin interaction, reducing relapse rates and progression of disease. Disclosures Forconi: Abbvie: Consultancy; Janssen-Cilag: Consultancy. Gribben:Abbvie: Honoraria; Roche: Honoraria; Pharmacyclics: Honoraria; Novartis: Honoraria; Cancer Research UK: Research Funding; Wellcome Trust: Research Funding; Acerta Pharma: Honoraria, Research Funding; TG Therapeutics: Honoraria; NIH: Research Funding; Kite: Honoraria; Janssen: Honoraria, Research Funding; Unum: Equity Ownership; Medical Research Council: Research Funding; Celgene: Consultancy, Honoraria, Research Funding.
21
Trebo, Anna, Nina Ditsch, Tom Degenhardt, Christina Kuhn, Martina Rahmeh, Elisa Schmoeckel, Doris Mayr, et al. "First Evidence for a Role of Siglec-8 in Breast Cancer." International Journal of Molecular Sciences 22, no. 4 (February 18, 2021): 2000. http://dx.doi.org/10.3390/ijms22042000.
Full textAbstract:
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are involved in various immune cell-mediated diseases. Their role in cancer is poorly investigated, and research focusses on Siglec-expression on immune cells interacting with tumor cells. This study evaluates the role of Siglec-8 in breast cancer (BC). Siglec-8 expression was analyzed immunohistochemically on 235 primary BC cases and was correlated with clinical and pathological parameters and outcome. Cell culture experiments were performed with various BC cell lines. Siglec-8 was expressed in 215 BC cases and expression was lowest in triple-negative BC. It correlated with estrogen receptor-status, grading and the prognostic factors galectin (Gal)-7 and tumor-associated mucin-1 (TA-MUC1). However, Gal-7 and TA-MUC1 were only prognosticators for clinical outcome in the cohort expressing high (Immunoreactivity score IRS > 3) Siglec-8 levels but not in the low-expressing cohort. Siglec-8 knockdown led to a significantly reduced Gal-7 expression in MCF7 cells. All BC cell lines expressed low Siglec-8-levels, that could be elevated in MCF7 by Peroxisome proliferator-activated receptor (PPARγ)-stimulation. This study demonstrates that Siglec-8 is expressed in BC cells and correlates with known clinical and prognostic parameters. It is probably associated with Gal-7 and TA-MUC1 and might be regulated via PPARγ. Further analyses focusing on functional associations will clarify Siglec-8’s eligibility as a possible therapeutic target.
22
Baum, L. G., M. Pang, N. L. Perillo, T. Wu, A. Delegeane, C. H. Uittenbogaart, M. Fukuda, and J. J. Seilhamer. "Human thymic epithelial cells express an endogenous lectin, galectin-1, which binds to core 2 O-glycans on thymocytes and T lymphoblastoid cells." Journal of Experimental Medicine 181, no. 3 (March 1, 1995): 877–87. http://dx.doi.org/10.1084/jem.181.3.877.
Full textAbstract:
Thymic epithelial cells play a crucial role in the selection of developing thymocytes. Thymocyte-epithelial cell interactions involve a number of adhesion molecules, including members of the integrin and immunoglobulin superfamilies. We found that human thymic epithelial cells synthesize an endogenous lectin, galectin-1, which binds to oligosaccharide ligands on the surface of thymocytes and T lymphoblastoid cells. Binding of T lymphoblastoid cells to thymic epithelial cells was inhibited by antibody to galectin-1 on the epithelial cells, and by two antibodies, T305 and 2B11, that recognize carbohydrate epitopes on the T cell surface glycoproteins CD43 and CD45, respectively. T lymphoblastoid cells and thymocytes bound recombinant galectin-1, as demonstrated by flow cytometric analysis, and lectin binding was completely inhibited in the presence of lactose. The degree of galectin-1 binding to thymocytes correlated with the maturation stage of the cells, as immature thymocytes bound more galectin-1 than did mature thymocytes. Preferential binding of galectin-1 to immature thymocytes may result from regulated expression of preferred oligosaccharide ligands on those cells, since we found that the epitope recognized by the T305 antibody, the core 2 O-glycan structure on CD43, was expressed on cortical, but not medullary cells. The level of expression of the UDP-GlcNAc:Gal beta 1,3GalNAc-R beta 1, 6GlcNAc transferase (core 2 beta 1, 6 GlcNAc transferase, or C2GnT), which creates the core 2 O-glycan structure, correlated with the glycosylation change between cortical and medullary cells. Expression of mRNA encoding the C2GnT was high in subcapsular and cortical thymocytes and low in medullary thymocytes, as demonstrated by in situ hybridization. These results suggest that galectin-1 participates in thymocyte-thymic epithelial cell interactions, and that this interaction may be regulated by expression of relevant oligosaccharide ligands on the thymocyte cell surface.
23
Gianchecchi, Elena, Andrea Arena, and Alessandra Fierabracci. "Sialic Acid-Siglec Axis in Human Immune Regulation, Involvement in Autoimmunity and Cancer and Potential Therapeutic Treatments." International Journal of Molecular Sciences 22, no. 11 (May 28, 2021): 5774. http://dx.doi.org/10.3390/ijms22115774.
Full textAbstract:
Siglecs are sialic acid-binding immunoglobulin-like lectins. Most Siglecs function as transmembrane receptors mainly expressed on blood cells in a cell type-specific manner. They recognize and bind sialic acids in specific linkages on glycoproteins and glycolipids. Since Sia is a self-molecule, Siglecs play a role in innate immune responses by distinguishing molecules as self or non-self. Increasing evidence supports the involvement of Siglecs in immune signaling representing immune checkpoints able to regulate immune responses in inflammatory diseases as well as cancer. Although further studies are necessary to fully understand the involvement of Siglecs in pathological conditions as well as their interactions with other immune regulators, the development of therapeutic approaches that exploit these molecules represents a tremendous opportunity for future treatments of several human diseases, as demonstrated by their application in several clinical trials. In the present review, we discuss the involvement of Siglecs in the regulation of immune responses, with particular focus on autoimmunity and cancer and the chance to target the sialic acid-Siglec axis as novel treatment strategy.
24
Miao, Hongzhi Z., Nongnuch Sirachainan, Lisa Palmer, Phillip Kucab, Michael A. Cunningham, Randal J. Kaufman, and Steven W. Pipe. "Bioengineering of coagulation factor VIII for improved secretion." Blood 103, no. 9 (May 1, 2004): 3412–19. http://dx.doi.org/10.1182/blood-2003-10-3591.
Full textAbstract:
Abstract Factor VIII (FVIII) functions as a cofactor within the intrinsic pathway of blood coagulation. Quantitative or qualitative deficiencies of FVIII result in the inherited bleeding disorder hemophilia A. Expression of FVIII (domain structure A1-A2-B-A3-C1-C2) in heterologous mammalian systems is 2 to 3 orders of magnitude less efficient compared with other proteins of similar size compromising recombinant FVIII production and gene therapy strategies. FVIII expression is limited by unstable mRNA, interaction with endoplasmic reticulum (ER) chaperones, and a requirement for facilitated ER to Golgi transport through interaction with the mannose-binding lectin LMAN1. Bioengineering strategies can overcome each of these limitations. B-domain-deleted (BDD)-FVIII yields higher mRNA levels, and targeted point mutations within the A1 domain reduce interaction with the ER chaperone immunoglobulin-binding protein. In order to increase ER to Golgi transport we engineered several asparagine-linked oligosaccharides within a short B-domain spacer within BDD-FVIII. A bioengineered FVIII incorporating all of these elements was secreted 15- to 25-fold more efficiently than full-length FVIII both in vitro and in vivo. FVIII bioengineered for improved secretion will significantly increase potential for success in gene therapy strategies for hemophilia A as well as improve recombinant FVIII production in cell culture manufacturing or transgenic animals. (Blood. 2004;103: 3412-3419)
25
Pramod, S. N., Y. P. Venkatesh, and P. A. Mahesh. "Potato lectin activates basophils and mast cells of atopic subjects by its interaction with core chitobiose of cell-bound non-specific immunoglobulin E." Clinical & Experimental Immunology 148, no. 3 (March 15, 2007): 391–401. http://dx.doi.org/10.1111/j.1365-2249.2007.03368.x.
Full text
26
Kim, Haekwon, and Allen W. Schuetz. "Structural and functional differentiation of follicular and oviductal mouse oocytes visualised with FITC-protein conjugates." Zygote 1, no. 4 (November 1993): 297–307. http://dx.doi.org/10.1017/s0967199400001623.
Full textAbstract:
SummaryThe fluroscence labelling characteristics of mouse oocytes were examined at various stages of periovulatory differentiation using FITC-protein conjugates. The zona pellucida perivitelline space and plasma membrane underwent visible changes which were developmentally and environmentally related. Following exposure to fluorescein isothiocyanate (FITC)-casein conjugates, the zona pellucida (ZP) of germinal vesicle stage (GV) ovarian oocytes exhibited a bright, amorphous, mesh-like staining pattern (immature type). In contrast, mature polar body stage (PB) oocytes, either ovarian or oviductal, displayed faint, spotty fluorescence labelling of the ZP (mature type). The perivitelline space (PVS) of mature ovarian oocytes (12 h post-hCG) failed to label, whereas approximately 50% of oviductal oocytes showed PVS labelling. The incidence of PVS staining increased with postovulatory age, possibly as a result of the accumulation of materials secreted by the oviduct. Following in vivo or in vitro fertilisation of oocytes, a characteristic pattern of plasma membrane (PM) labelling was observed. Similar patterns of PM labelling were seen in oocytes parthenogenetically activated with ethanol or ionophore (A23187) but not in control oocytes. The pattern of PM labelling observed with FITC-protein conjugates was strikingly similar to that observed with FITC-labelled lectins, which are thought to interact with glycoconjugates released from cortical granules. Immature type of ZP staining also occurred when GV oocytes were treated with FITC alone or with a variety of FITC-protein conjugates. Thus, protein may not be required for labelling of the ZP by FITC-protein conjugates as previously thought. FITCconjugated proteins including casein, bovine serum albumin, peroxidase and non-immune immunoglobulin G (IgG), all labelled the PM of activated oocytes; however, FITC-IgG failed to label the PVS. Results demonstrate for the first time that various components of viable mouse oocytes exhibit and undergo characteristic structural and functional changes during periovulatory differentiation as evidenced by their interaction with one or more FITC-protein conjugates and/or FITC. On the basis of these results the intrafollicular and oviductal mechanisms mediating these changes are discussed as is the possibility that the fluorescent molecule attached to conjugates may play a role in oocyte labelling.
27
Pegon, Julie N., Cécile V. Denis, Soline Odouard, Olivier D. Christophe, and Peter J. Lenting. "Siglecs as Novel Cellular Partners for Von Willebrand Factor." Blood 116, no. 21 (November 19, 2010): 4306. http://dx.doi.org/10.1182/blood.v116.21.4306.4306.
Full textAbstract:
Abstract Abstract 4306 Introduction: Von Willebrand factor (VWF) is a multimeric protein that is pertinent to the haemostatic process by promoting platelet recruitment to the growing thrombus and acting as a carrier-protein for factor VIII. It is well established that VWF is able to interact with several cellular receptors present on the surface of platelets and leukocytes. In search for novel cellular partners for VWF present on these cells, we made use of the notion that VWF is heavily glycosylated, with the mature molecule containing 12 N-linked glycans and 10 O-linked glycans. Importantly, the vast majority of these glycans (>90%) are sialylated. The human proteome contains a family of sialic acid-binding receptors, known as Sialic acid-binding Immunoglobulin-like Lectins (Siglecs), which are expressed on cells of hematopoietic origin. The current study was designed to investigate the potential of Siglecs to interact with VWF. Methods: Stable human HEK293 cell lines were established that express human Siglec-5, Siglec-7 or Siglec-9. In addition, soluble variants of Siglecs were obtained: monomeric HPC4-tagged Siglec-5 and Siglec-7 (sSg5/HPC4 & sSg7/HPC4) and dimeric Fc-fusion proteins for human Siglec-3, -5, -7, -9, -10, -11 and murine Siglec-F (sSg-3/Fc etc). These Siglecs were used to study their interaction with purified plasma-derived (pdVWF) or recombinant BHK-cell derived VWF (rVWF). Protein-protein interactions were investigated via immuno-sorbent assays and via surface plasmon resonance (SPR) using Octet QK equipment. Binding of VWF to Siglec-expressing cells was assessed via immuno-fluorescence microscopy. Results: We observed consistent association of VWF (irrespective whether immuno-sorbent or SPR assays were used) to all of the immobilized Siglecs tested, with the exception of sSg-11/Fc that did not interact with pdVWF or with rVWF. Inversely, all soluble Siglecs but sSg-11/Fc efficiently bound to immobilized pdVWF or rVWF. Half-maximal binding in immuno-sorbent assays was between 97 and 645 nM (binding of VWF to immobilized Siglecs) versus 166 and 270 nM (binding of Siglecs to immobilized VWF). More detailed studies on the determination of the kinetic parameters using SPR technology are in progress. Specificity of the interaction was confirmed by treating VWF with sialidase before testing Siglec binding, and such treatment resulted in a strongly reduced (up to 80%) ability of Siglecs to bind to immobilized VWF. VWF was further found to bind to Siglec-5, -7 or -9 expressing HEK293 cells as assessed via immuno-fluorescence microscopy. In general, 10–15 % of the Siglec-expressing cells were covered with VWF after incubation, with the fluorescent intensity increasing dose-dependently with the applied VWF concentration. No fluorescent signal was observed upon incubation of VWF with non-transfected cells or when VWF was omitted from the incubation. Since Siglecs may be masked by the presence of endogenous sialylated proteins at the cellular surface, we also tested VWF binding to these cells following sialidase treatment. Sialidase treatment of cells resulted in a marked increase in the number of VWF-binding cells (up to 80% of the Siglec-positive cells) as well as an increase in intensity of the fluorescent signal. Co-localization of VWF with Siglecs at the cellular surface was confirmed by DuoLink-analysis, which allows the detection of proteins that are in the vicinity of ≤40 nm. Emerging evidence demonstrates that endothelial. Conclusions: We identified one murine and six human Siglec-family members as novel partners for VWF. Interactions between VWF and Siglecs are mediated by sialic acid structures present on VWF. In addition, the cellular accessibility of Siglecs for VWF is modulated by cis-acting sialylated proteins at the cell surface. In conclusion, our data demonstrate that the VWF glycome allows the interaction with a novel family of cellular receptors, potentially opening previously unrecognized avenues in the biology of VWF. Disclosures: No relevant conflicts of interest to declare.
28
Taylor, James G., Gila Idelman, Ron Tongbai, Renee A. Chen, Cynthia M. Haggerty, Stephen Jacob Chanock, and Kevin Gardner. "vRare VCAM1 Promoter Haplotypes Prevalent in African Americans Are Hyperinducible." Blood 108, no. 11 (November 16, 2006): 1813. http://dx.doi.org/10.1182/blood.v108.11.1813.1813.
Full textAbstract:
Abstract Cell adhesion molecules direct the inflammatory response through cell-cell interactions between leukocytes and endothelial cells, leukocyte trafficking, and cell signaling. Vascular cell adhesion molecule 1 (VCAM1) is a member of the CAM immunoglobulin superfamily whose expression at the cell surface is highly tissue and mitogen specific. Because genetic variation in VCAM1 has been implicated in the pathogenesis of a variety of human diseases, we sought a method for rapidly identifying functional simple nucleotide polymorphsisms (SNPs) present within a discrete non-coding regulatory regions of this gene. Using a novel transfection-based transcriptional pathway profiling method, we show that several uncommon variant haplotypes are functionally hyperactive. Initially, DNA sequencing across the 2.5 kb VCAM1 promoter in a screening population of 40 healthy African Americans identified 21 SNPs that define 18 different promoter haplotypes. Eight of these promoter haplotypes, defined by 13 SNPs and representing 80% of the haplotypes present in the screening population, were then evaluated for response to 5 hour stimulation with known mitogens in transient transfections of Jurkat T cells. Transcriptional reporter activity in response to combinations of phorbol ester, lectins and ionophore were clustered by inducibility using principal component analysis (PCA). Three uncommon haplotypes, each with frequencies of less than 5% in the controls, were clearly identified by PCA as hyperactive in response to mitogens. Next, in vitro haplotype activity was correlated with a bioinformatic analysis of transcription factor binding site gains or losses created by 11 of the 13 variant nucleotide sites and unique to each haplotype. Using this approach, a low frequency regulatory allele (A-540G), present on one of the hyperactive VCAM1 promoter haplotypes (haplotype 5), was identified as a putative binding site for the transcription factor ETS2. The selective gain of the ETS binding site was confirmed in vivo by chromatin immunoprecipitation experiments comparing two lymphblastoid cell lines (LCLs) of known genotype. An LCL heterozygous for the hyperactive VCAM1 haplotype 5 demonstrated nearly an 8 fold enrichment in ETS2 complexes at the VCAM1 promoter relative to a cell line homozygous for the wild type alleles. Together, these results suggest that some variants in the VCAM1 promoter alter function by changing the affinity of specific transcription factors for their DNA binding sites. This study provides the first functional evaluation of VCAM1 promoter polymorphisms and establishes a hypothetical foundation for investigating specific VCAM1 functional variants in the pathogenesis of complex genetic diseases that disproportionately afflict African Americans, including hemoglobinopathies, asthma, and hematopoietic malignancies. Overall, this study demonstrates feasibility of combining a series of genetic, bioinformatic, and wet lab methodologies for rapid identification of functional genetic variants within a larger pool of SNPs present across non-coding and regulatory regions of human genes.
29
Wollenberg, A., H. de la Salle, D. Hanau, F. T. Liu, and T. Bieber. "Human keratinocytes release the endogenous beta-galactoside-binding soluble lectin immunoglobulin E (IgE-binding protein) which binds to Langerhans cells where it modulates their binding capacity for IgE glycoforms." Journal of Experimental Medicine 178, no. 3 (September 1, 1993): 777–85. http://dx.doi.org/10.1084/jem.178.3.777.
Full textAbstract:
A better understanding of the pathophysiological role of Langerhans cells (LC) in atopic diseases is dictated by the characterization of the structures involved in immunoglobulin (IgE)-binding on their cell surface. We previously reported that human LC express the high affinity receptor for IgE (Fc epsilon RI), as well as the low affinity receptor for IgE (Fc epsilon RII/CD23). In the present study, we document the presence of a third IgE-binding structure on human LC, the IgE-binding protein (epsilon BP), an endogenous soluble beta-galactoside binding lectin. Immunohistochemical studies performed on normal human skin revealed an anti-epsilon BP reactivity in the cytoplasm of keratinocytes and in that of acinous cells of eccrine sweat glands. epsilon BP was also found on the cell surface of LC, as shown by anti-epsilon BP/anti-CD1a double labeling and flow cytometric analysis. Anti-epsilon BP binding to the surface of LC was completely abolished by preincubation with lactose and restored by addition of recombinant human epsilon BP, indicating that epsilon BP binds to LC surface by virtue of its lectin property. Immunoblot analysis of anti-epsilon BP-reactive material in keratinocytes and purified LC disclosed a protein with an apparent molecular weight of 33,000 consistent with epsilon BP. Interestingly, mRNA transcripts for epsilon BP were detected only in keratinocytes but not in purified LC isolated from normal skin. epsilon BP was found to be released in culture supernatants of keratinocytes. Incubation of LC with these supernatants resulted in epsilon BP-binding to LC surface via protein-carbohydrate interaction. Most importantly, we could show that binding of human myeloma IgE to LC was inhibited by epsilon BP. In contrast, neuraminidase-treated human myeloma IgE binds to LC only in the presence of epsilon BP. In situ binding studies revealed that keratinocytes, although containing epsilon BP intracytoplasmatically, failed to exhibit any IgE-binding properties. Collectively, our results suggest that human keratinocytes produce the beta-galactoside-binding lectin epsilon BP, which subsequently binds to the surface of LC where it is functional in modulating their binding capacity for IgE glycoforms.
30
Stringaris, Kate, Takuye Sekine, Ahmad Khoder, Abdullah Alsuliman, Pavlu Jiri, Anushruthi Sarvaria, David Marin, Jane Apperley, A. John Barrett, and Katayoun Rezvani. "Defective Natural Killer (NK) Receptor Expression and Effector Function in Acute Myeloid Leukemia Partially Normalize At Remission and Predict Response to Chemotherapy." Blood 120, no. 21 (November 16, 2012): 2591. http://dx.doi.org/10.1182/blood.v120.21.2591.2591.
Full textAbstract:
Abstract Abstract 2591 Despite favorable initial responses to induction chemotherapy, most patients with acute myeloid leukemia (AML) will relapse. We hypothesized that just as cancers evade immunosurveillance by suppressing the immune response (“immunoediting”), remission and relapse in AML may be determined by similar immune interactions. After stem cell transplantation natural killer (NK) cells exert powerful allogeneic graft vs. leukemia effects. To explore immunosurveillance by autologous NK cells and immunoediting by AML blasts, we prospectively analyzed NK surface phenotype and function in AML patients at presentation and following remission induction. Using multi-color flow cytometry, we analyzed the surface expression of natural cytotoxicity receptors (NCRs), killer immunoglobulin receptors (KIRs) and C-type lectins directly ex-vivo in 32 consecutive patients at presentation and following complete remission (CR) in 12 patients for whom remission samples were available. Results were compared with 15 healthy controls. NK effector function in AML was measured against K562 leukemia targets and autologous AML blasts by CD107a degranulation and interferon-gamma (IFNγ) and TNF-alpha (TNFα) production. NK cells from 32 patients with AML at diagnosis had an abnormal phenotype compared to controls, with downregulation of the activatory receptor NKp46 (MFI 187± 15 vs. 266± 24, p=0.007) and upregulation of the inhibitory receptor NKG2A (mean 45%± 4.2 vs. 32%± 2.7, p=0.046). Moreover, AML-NK cells were defective in their effector function with significantly reduced CD107a degranulation (5% vs. 11%, p=0.0002), TNFα (1% vs. 3%, p=0.008) and IFNγ production (1% vs. 5%, p=<0.0001). In the 12 patients who achieved remission following induction chemotherapy NKp46 expression normalized from an MFI 122 at presentation to 242 (p=0.01); however, NKG2A expression continued to increase (45% vs. 61%, p=0.008). At remission AML-NK cells displayed CD107a degranulation levels comparable to that of healthy donor NK cells (9% vs. 11%, p=0.4). In contrast, TNFα and IFNγ production only partially normalized (2% vs. 3%, p=0.3) and (3% vs. 5%, p=0.04), respectively. AML patients with NKG2A overexpression (> median of 32.6%) at diagnosis were significantly less likely to achieve CR post chemotherapy compared to those with lower NKG2A expression (78% vs. 32% p= 0.041). Furthermore, patients who failed to respond to induction chemotherapy had significantly reduced NK effector function at diagnosis compared to normal controls (mean TNFα production 1% cf. 5% p=0.019). We then sought for evidence of immunoediting by AML on NK cell phenotype and function. Co-incubation of healthy donor NK cells with primary AML blasts for 24 hours resulted in significant reduction in TNFα production (p=0.02), IFNγ production (p=0.01) and a trend to reduced CD107a degranulation (p=0.07) against K562 leukemia targets. Our results indicate that AML blasts can produce long-lasting changes in NK cell subsets and impair their effector function and favouring immune escape from NK cell control. This work justifies larger prospective analyses to relate NK-based prognostic factors to classical predictive factors for remission and relapse, and should guide the development of NK cell based immunotherapy to improve outcome in AML. Disclosures: No relevant conflicts of interest to declare.
31
Rudensky, Alexander Y., and Vitalij L. Yurin. "Immunoglobulin-specific T-B cell interaction." European Journal of Immunology 19, no. 9 (September 1989): 1677–83. http://dx.doi.org/10.1002/eji.1830190923.
Full text
32
Yurin, Vitalij L., Alexander Y. Rudensky, Svetlana M. Mazel, and Janna M. Blechman. "Immunoglobulin-specific T-B cell interaction." European Journal of Immunology 19, no. 9 (September 1989): 1685–91. http://dx.doi.org/10.1002/eji.1830190924.
Full text
33
Koneti, Adi, Michael J. Linke, Elmer Brummer, and David A. Stevens. "Evasion of Innate Immune Responses: Evidence for Mannose Binding Lectin Inhibition of Tumor Necrosis Factor Alpha Production by Macrophages in Response to Blastomyces dermatitidis." Infection and Immunity 76, no. 3 (December 10, 2007): 994–1002. http://dx.doi.org/10.1128/iai.01185-07.
Full textAbstract:
ABSTRACT Serum factors, including mannose binding lectins (MBL), influence innate responses to microbes. Little is known about the effects of serum factors or MBL on the interaction of Blastomyces dermatitidis, a pulmonary fungal pathogen, with macrophages or on tumor necrosis factor alpha (TNF-α) production. Since macrophage production of TNF-α is an important innate immune response, we examined a mouse peritoneal macrophage (PM) cell line (RAW) and resident PM from CD-1 mice to study TNF-α production by PM stimulated with heat-killed (HK) or live B. dermatitidis yeast cells. Mouse serum and heat-inactivated mouse serum inhibited TNF-α production 94% when macrophages were stimulated by B. dermatitidis, whereas mouse immunoglobulin G (IgG) did not have this effect. HK B. dermatitidis incubated with serum and then washed also failed to stimulate significant TNF-α production by PM. By the sandwich immunofluorescent antibody (IFA) method with anti-mouse MBL (MBL-A or -C), we showed that serum MBL bound to B. dermatitidis. When serum was absorbed with HK B. dermatitidis or live B. dermatitidis, absorbed serum failed to significantly inhibit TNF-α production by RAW cells plus B. dermatitidis, and immunoblotting showed that absorbed serum was depleted of MBL-C. If serum was absorbed with live B. dermatitidis, unbound serum was eluted, and bound serum factor(s) (BS) was released with guanidine buffer, BS inhibited TNF-α production by PM plus B. dermatitidis in a concentration-dependent manner. BS contained MBL-C, which bound B. dermatitidis, as shown by IFA assay. 1,3-β-Glucan stimulated TNF-α production by PM, and this was inhibited by mouse serum. Treatment of B. dermatitidis with anti-1,3-β-glucan antibody inhibited TNF-α production by PM. With anti-1,3-β-glucan antibody, we showed by IFA assay that B. dermatitidis contained 1,3-β-glucan. In an IFA study with B. dermatitidis, serum with an anti-mouse IgG conjugate did not result in fluorescence, yet serum blocked IFA staining of B. dermatitidis by anti-1,3-β-glucan IgG antibody. This indicated that non-IgG serum factors binding to B. dermatitidis prevented access to 1,3-β-glucan by anti-1,3-β-glucan antibody. These results suggest that the mechanism of inhibition of the innate proinflammatory immune response of PM to B. dermatitidis is mediated by serum MBL binding to B. dermatitidis at 1,3-β-glucan sites or sterically masking 1,3-β-glucan sites, thus preventing 1,3-β-glucan stimulation of PM for TNF-α production.
34
Brown, Harrison C., Bagirath Gangadharan, and Christopher Doering. "Differential Engagement of the Unfolded Protein Response by Human and Porcine Factor VIII." Blood 116, no. 21 (November 19, 2010): 2224. http://dx.doi.org/10.1182/blood.v116.21.2224.2224.
Full textAbstract:
Abstract Abstract 2224 Despite 83% amino acid sequence identity, human factor VIII (fVIII) and porcine fVIII display a striking species-specific expression differential (10 – 100- fold) that may be relevant to each species’ maintenance of hemostasis. This expression differential has been exploited for the development of improved recombinant fVIII therapeutics and gene-transfer-based therapies (Doeringet al., JBC 2002, JBC 2004; Gangadharanet al., Blood 2006; Doeringet al., Mol. Ther. 2007; Doeringet al., Mol. Ther. 2009; Doorisset al., Hum. Gene Ther. 2009). The exact biochemical or cellular mechanisms responsible for this phenomenon has yet to be uncovered. However, the expression differential has been temporally and spatially localized to post-translational steps that occur in the endoplasmic reticulum (ER)/golgi apparatus (Doeringet al., JBC 2004). The unfolded protein response (UPR) is a coordinated cellular mechanism designed to regulate the build-up and flow of proteins in the ER and is sometimes referred to as the “quality control pathway”. Early studies of recombinant fVIII production in heterologous cell culture systems uncovered that human fVIII biosynthesis induces up-regulation of the UPR through interaction with immunoglobulin binding protein (BiP)/glucose regulated protein 78 (GRP78). These studies prompted the speculation that human fVIII may not undergo correct secondary and tertiary folding efficiently or, alternatively, may display thermodynamic instability subsequent to initial folding. Either event could serve to induce UPR activity and affect overall fVIII biosynthesis. In the current study, we hypothesized that the differential in biosynthesis between recombinant human and porcine fVIII results from differential engagement of the UPR pathway. To test this hypothesis, we studied the UPR response during expression of recombinant human and porcine fVIII in heterologous baby hamster kidney cells. In experiments utilizing a ER response element (ERSE)-luciferase reporter construct, human fVIII expression was shown to increase luciferase activity 2-fold over that observed with porcine fVIII despite the secretion of 10-fold more porcine fVIII based on activity measurement of the conditioned medium. Human fVIII expression also induced X-box protein 1 (XBP-1) splicing, another marker of UPR activation, to a greater extent than did porcine fVIII expression (2-fold versus 1.1-fold over naïve BHK cells, respectively). Immunofluorescence microscopy of fVIII expressing cells revealed that human fVIII almost exclusively was localized to the ER and displayed significant co-localization with BiP, a resident ER luminal protein. In contrast, a significant proportion of porcine fVIII antigen was localized to the Golgi apparatus and co-localized with the lectin, wheat germ agglutinin (r2 = 0.8 versus 0.6 for human fVIII), suggesting more efficient transit through the secretory pathway. Perturbation of the intracellular BiP levels by transduction of fVIII expressing BHK cells with recombinant lentivector encoding BiP revealed that, under normal conditions, BiP levels may actually be limiting in terms of the interaction with human fVIII. Over-expression of BiP (6.5-fold increased BiP mRNA levels) reduced the secretion of human fVIII by 50%, whereas the same BiP over-expression had no affect on porcine fVIII biosynthesis. In neither case were fVIII mRNA levels negatively affected by BiP over-expression. In contrast, transduction of fVIII expressing BHK cells with lentivector encoding shRNA targeting BiP led to 2-fold improvement in human fVIII expression levels. Again, these data support a role of BiP in the impediment of human fVIII biosynthesis that is not equivalent for porcine fVIII. Therefore, differential engagement of the UPR by human and porcine fVIII was observed in the current study, thus supporting a dominant role of protein folding/stability characteristics in the expression differential present among porcine and human fVIII. This study also demonstrates that the investigation of orthologous protein biosynthesis can yield important insights into the regulation of gene product levels through non-traditional mechanisms. Disclosures: No relevant conflicts of interest to declare.
35
Aguilar, Ethan G., Can M. Sungur, Anthony E. Zamora, and William J. Murphy. "Evidence That Novel NK-NK Cell Subset Regulation Exists With Regard To Effects In Tumor and Viral Models." Blood 122, no. 21 (November 15, 2013): 1038. http://dx.doi.org/10.1182/blood.v122.21.1038.1038.
Full textAbstract:
Abstract Natural killer (NK) cells are lymphocytes of the innate immune system and are classically associated with cytotoxic responses to both virally infected as well as neoplastic cells. Activation of NK cells to exhibit their cytotoxicity is dependent on signaling through a number of activating and inhibitory receptors. In mice, one such family of inhibitory receptors is the C-type lectin-like Ly49 family. In humans, the killer immunoglobulin-like receptors (KIRs) serve as the primary family of inhibitory receptors and are functional analogs of the Ly49s. Despite markedly different structures, the Ly49s and KIRs display similar binding capabilities and bind primarily to distinct MHC class I haplotypes, which plays an important role in regulating NK cell function. NK cells that express inhibitory receptors that are specific for the MHC class I haplotype of the individual are termed “licensed” and have been shown to have increased functionality in terms of cytotoxicity and cytokine production. In contrast, NK cells that express inhibitory receptors that are unable to bind to the MHC class I haplotype of the individual are termed “unlicensed” and have been shown to be hyporesponsive. We have recently reported on the role of NK licensing on the immune response to viral infections such as MCMV. In addition, we have previously described how regulatory T cells can regulate NK cell activity in vivo. However, there are limited data examining the interaction and regulation between the different NK subsets based on differences in licensing. We hypothesized that different NK cell subsets, based on licensing, can regulate each other in the context of anti-tumor and anti-viral responses. Here we first provide in vitro data providing evidence to support the hypothesis of NK-NK regulation based on licensing. In vitro killing assays using MCMV infected fibroblasts, or C1498 (murine acute myeloid leukemia) cells as targets and using different combinations of murine NK Ly49 subsets as effectors were used to assess this NK-NK regulation. To further test our hypothesis, in vivo experiments were also performed using a mouse leukemia model as well as an MCMV model. Mice were injected with C1498 cells and then given hematopoietic stem cell transplantation (HSCT). The mice were then depleted of all NK cells or either licensed or unlicensed subsets by antibody depletion once a week, and monitored for survival. Mice that were depleted of the unlicensed population survived significantly longer compared with the other depleted groups, suggesting a negative regulation of the anti-tumor response by the unlicensed population resulting in greater tumor burden and death in the presence of the unlicensed population. This negative regulation by the unlicensed population is further supported by another experiment where mice were infected with MCMC following total NK or subset depletion and monitored for ten days throughout the course of the immune response to MCMV. Mice that were depleted of their unlicensed population displayed a significantly larger expansion of the licensed population of NK cells, without reciprocal greater expansion of the unlicensed population upon licensed NK cell depletion. More specifically, depletion of the unlicensed population resulted in an expansion of the Ly49H+NK cells which have previously been shown to be the primary effector population during MCMV infection. Thus, the unlicensed NK cells are playing a role in down-regulating the anti-viral response by limiting the expansion of the effector licensed population. Our data highlight a role for the murine NK subsets to negatively regulate the immune response of the effector licensed NK population in the context of anti-tumor and anti-viral responses. This new insight into the regulatory role of NK cells may have clinical benefit for patients receiving bone marrow transplants during cancer treatment to enhance graft vs. tumor effects, and to combat opportunistic viral infections that may manifest in the immune compromised environment of the BMT patient. Disclosures: No relevant conflicts of interest to declare.
36
Sung, L. A., E. A. Kabat, and S. Chien. "Interaction of lectins with membrane receptors on erythrocyte surfaces." Journal of Cell Biology 101, no. 2 (August 1, 1985): 646–51. http://dx.doi.org/10.1083/jcb.101.2.646.
Full textAbstract:
The interactions of human genotype AO erythrocytes (red blood cells) (RBCs) with N-acetylgalactosamine-reactive lectins isolated from Helix pomatia (HPA) and from Dolichos biflorus (DBA) were studied. Binding curves obtained with the use of tritium-labeled lectins showed that the maximal numbers of lectin molecules capable of binding to human genotype AO RBCs were 3.8 X 10(5) and 2.7 X 10(5) molecules/RBC for HPA and DBA, respectively. The binding of one type of lectin may influence the binding of another type. HPA was found to inhibit the binding of DBA, but not vice versa. The binding of HPA was weakly inhibited by a beta-D-galactose-reactive lectin isolated from Ricinus communis (designated RCA1). Limulus polyphemus lectin (LPA), with specificity for N-acetylneuraminic acid, did not influence the binding of HPA but enhanced the binding of DBA. About 80% of LPA receptors (N-acetylneuraminic acid) were removed from RBC surfaces by neuraminidase treatment. Neuraminidase treatment of RBCs resulted in increases of binding of both HPA and DBA, but through different mechanisms. An equal number (7.6 X 10(5) of new HPA sites were generated on genotypes AO and OO RBCs by neuraminidase treatment, and these new sites accounted for the enhancement (AO cells) and appearance (OO cells) of hemagglutinability by HPA. Neuraminidase treatment did not generate new DBA sites, but increased the DBA affinity for the existing receptors; as a result, genotype AO cells increased their hemagglutinability by DBA, while OO cells remained unagglutinable. The use of RBCs of different genotypes in binding assays with 3H-labeled lectins of known specificities provides an experimental system for studying cell-cell recognition and association.
37
Duan, Shiteng, and James C. Paulson. "Siglecs as Immune Cell Checkpoints in Disease." Annual Review of Immunology 38, no. 1 (April 26, 2020): 365–95. http://dx.doi.org/10.1146/annurev-immunol-102419-035900.
Full textAbstract:
Sialic acid–binding immunoglobulin-type lectins (Siglecs) are expressed on the majority of white blood cells of the immune system and play critical roles in immune cell signaling. Through recognition of sialic acid–containing glycans as ligands, they help the immune system distinguish between self and nonself. Because of their restricted cell type expression and roles as checkpoints in immune cell responses in human diseases such as cancer, asthma, allergy, neurodegeneration, and autoimmune diseases they have gained attention as targets for therapeutic interventions. In this review we describe the Siglec family, its roles in regulation of immune cell signaling, current efforts to define its roles in disease processes, and approaches to target Siglecs for treatment of human disease.
38
Gleason, Michelle, Todd Lenvik, Valarie McCullar, Sarah Cooley, Michael Verneris, Toshiro Niki, Mitsuomi Hirashima, Bruce R. Blazar, and Jeffrey S. Miller. "Tim-3, a Novel Immune Receptor, Is Constitutively Expressed on Human Natural Killer Cells and Functions as An Activating Coreceptor." Blood 116, no. 21 (November 19, 2010): 106. http://dx.doi.org/10.1182/blood.v116.21.106.106.
Full textAbstract:
Abstract Abstract 106 NK cells are an attractive option for immunotherapy as they do not require pre-sensitization for anti-tumor activity and do not induce graft versus host disease (GvHD) in an allogeneic transplant setting. The potential of NK cells in controlling human hematological malignancies has been increasingly recognized in recent years, as the adoptive transfer of alloreactive NK cells in hematopoietic cell transplantation (HCT) clinical trials have demonstrated therapeutic anti-leukemia effects. NK cell function is regulated by the integration of antagonist signals received from cell surface activating and inhibitory receptors. Tim-3 is a novel immune receptor that is a member of the T cell immunoglobulin and mucin-containing domain (TIM) family of glycoproteins. While its role in T cells and antigen presenting cells has been described, little is known about its function in human NK cells. While Tim-3 is present on a variety of immune cells, resting NK cells constitutively express Tim-3 compared to other lymphocyte populations (NK: 73±3%; NKT: 6±1%; T: 1±1%; n=14) and we hypothesized that Tim-3 may be important in mediating NK cell function. The unique subset of cytokine producing CD56Bright NK cells exhibited significantly lower resting Tim-3 expression compared to CD56Dim NK cells (53±3% vs. 75±3%; p<0.001, n=14). Distinct Tim-3 expression patterns were found on resting CD56Dim NK cells and activation with low dose IL-12 (1ng/mL) and IL-18 (10ng/mL), intended to more closely mimic physiologic conditions, resulted in further differentiation of this unique expression pattern dividing NK cells into 4 distinct populations: Tim-3 was homogeneously up-regulated on all CD56Bright NK cells after activation while CD56Dim NK cells were further stratified into 3 defined populations with Tim-3hi, Tim-3lo and Tim-3neg expression. The only identified ligand of Tim-3 is galectin-9 (Gal-9), a β-galactoside binding lectin, which is expressed on a wide range of healthy and malignant cells. To investigate the potential function of Tim-3, an expression vector containing human Gal-9 was transduced into K562 and Raji cells, both without endogenous Gal-9 expression. Resting NK cytotoxicity (51Cr release) was found to be increased in the presence of Gal-9 compared to the non-Gal-9 expressing targets [E:T=0.7:1, K562 vs. K562-Gal-9: 25±3% vs. 33±3% (n=8, p<0.05); E:T=20:1, Raji vs. Raji-Gal-9: 8±1% vs. 17±2% (n=4, p<0.05)]. Analysis of CD107a degranulation showed that resting Tim-3+ CD56Bright cells were more functional against Gal-9 expressing targets than Tim-3− CD56Bright cells, suggesting that Tim-3 might also play a role in IFN-γ production. To further investigate this, resting NK cells were activated with low-dose IL-12/IL-18 overnight and IFN-γ levels were measured in response to soluble rhGal-9 (0, 2.5, 5, 10 and 20nM). Exposure to soluble rhGal-9 alone without IL-12/IL-18 did not induce IFN-γ production. For both the CD56Bright and CD56Dim IL-12/IL-18 activated NK populations, only Tim-3+ NK cells displayed a dose dependent increase in IFN-γ production upon exposure to soluble rhGal-9 compared to Tim-3− NK cells. To understand the relevance of the distinct Tim-3 populations circulating in resting blood, CD56Bright, CD56Dim/Tim-3hi, CD56Dim/Tim-3lo and CD56Dim/Tim-3neg populations were sorted, cultured overnight in IL-12/IL-18 and exposed to soluble rhGal-9. Results showed the Tim-3 expressing populations contain the predominant IFN-γ producing cells that were responsive to rhGal-9 (results for the sorted CD56Dim/Tim-3lo population shown in the figure below). This increase in IFN-γ production within the Tim-3 expressing NK cell populations was abrogated by the addition of β-lactose, a β-galactoside that binds and blocks Gal-9 activity. Lastly, Western blot and immunohistochemistry analysis of human primary acute leukemia blasts revealed high Gal-9 expression. As the presence of ligands for NK cell activating receptors on tumors provide an important prerequisite for NK cell activation and effector function, we show a novel functional role for the receptor Tim-3 in human NK cell biology in the presence of its ligand Gal-9. We, therefore, propose a model where constitutively expressed Tim-3 is up-regulated by NK cell activation and effector function is enhanced by Tim-3/Gal-9 interaction, which may potentiate the elimination of Gal-9 positive tumors by NK cells. Disclosures: Niki: GalPharma: Membership on an entity's Board of Directors or advisory committees. Hirashima:GalPharma: Membership on an entity's Board of Directors or advisory committees.
39
Mazel, Svetlana M., Alexander Y. Rudensky, and Vitalij L. Yurin. "Immunoglobulin-specific T-B cell interaction III. B cell activation by immunoglobulinrecognizing T cell clones." European Journal of Immunology 20, no. 4 (April 1990): 833–39. http://dx.doi.org/10.1002/eji.1830200418.
Full text
40
Horstkorte, R., M. Schachner, J. P. Magyar, T. Vorherr, and B. Schmitz. "The fourth immunoglobulin-like domain of NCAM contains a carbohydrate recognition domain for oligomannosidic glycans implicated in association with L1 and neurite outgrowth." Journal of Cell Biology 121, no. 6 (June 15, 1993): 1409–21. http://dx.doi.org/10.1083/jcb.121.6.1409.
Full textAbstract:
We have previously shown that the neural adhesion molecules L1 and NCAM interact with each other to form a complex which binds more avidly to L1 than L1 to L1 alone (Kadmon, G., A. Kowitz, P. Altevogt, and M. Schachner. 1990a. J. Cell Biol. 110:193-208). This cis-association between L1 and NCAM is carbohydrate-dependent (Kadmon, G., A. Kowitz, P. Altevogt, and M. Schachner. 1990b. J. Cell Biol. 110:209-218). In the present study, we report that L1 and NCAM bind to each other via oligomannosidic carbohydrates expressed by L1, but not by NCAM, as shown in several experiments: (a) complex formation between L1 and NCAM is inhibited by a mAb to oligomannosidic carbohydrates and by the oligosaccharides themselves; (b) NCAM binds to oligomannosidic carbohydrates; (c) within the L1/NCAM complex, the oligomannosidic carbohydrates are hidden from accessibility to a mAb against oligomannosidic carbohydrates; (d) the recombinant protein fragment of NCAM containing the immunoglobulin-like domains and not the fragment containing the fibronectin type III homologous repeats binds to oligomannosidic glycans. Furthermore, the fourth immunoglobulin-like domain of NCAM shows sequence homology with carbohydrate recognition domains of animal C-type lectins and, surprisingly, also with plant lectins. A peptide comprising part of the C-type lectin consensus sequence in the fourth immunoglobulin-like domain of NCAM interferes with the association between L1 and NCAM. The functional importance of oligomannosidic glycans at the cell surface was shown for neurite outgrowth in vitro. When neurons from early postnatal mouse cerebellum were maintained on laminin or poly-L-lysine, neurite outgrowth was inhibited by oligomannosidic glycans, by glycopeptides, glycoproteins, or neoglycolipids containing oligomannosidic glycans, but not by nonrelated oligosaccharides or oligosaccharide derivates. Neurite outgrowth was also inhibited by the peptide comprising part of the C-type lectin consensus sequence in the fourth immunoglobulin-like domain of NCAM. The combined results suggest that carbohydrate-mediated cis-associations between adhesion molecules at the cell surface modulate their functional properties.
41
Qiao, R., A. Siflinger-Birnboim, H. Lum, C. Tiruppathi, and A. B. Malik. "Albumin and Ricinus communis agglutinin decrease endothelial permeability via interactions with matrix." American Journal of Physiology-Cell Physiology 265, no. 2 (August 1, 1993): C439—C446. http://dx.doi.org/10.1152/ajpcell.1993.265.2.c439.
Full textAbstract:
We studied the effects of albumin and the lectin Ricinus communis agglutinin (RCA) on hydraulic conductivity (Lp) of bovine pulmonary microvascular endothelial cell monolayers (BPMVEC) because of the evidence that albumin and RCA can interfere with transendothelial albumin permeability (Siflinger-Birnboim, A., J. Schnitzer, H. Lum, F. Blumenstock, C. Shen, P. Del Vecchio, and A. Malik. J. Cell. Physiol. 149: 575-584, 1991). BPMVEC were seeded on microporous polycarbonate filters, and the liquid flux was measured by collecting effluent into a tubing of known inner diameter at transendothelial hydrostatic pressures (P) ranging from 5 to 20 cmH2O. Lp was calculated as the slope of the relationship of liquid flux per unit surface area (Jv) vs. P. Addition of RCA (50 micrograms/ml) or albumin (5 mg/ml) to the endothelial cell medium containing albumin-free Hanks' balanced saline solution (HBSS) decreased total Lp (expressed x 10(-6) cm.s-1 x cmH2O-1) from 17.2 +/- 3.6 during HBSS to 4.7 +/- 0.9 during albumin and 5.7 +/- 1.6 during RCA (P < 0.01 for both). The RCA effect, but not that of albumin, was prevented by the addition of D-galactose (0.1 M) (the cognate hapten monosaccharide of RCA). We determined the contribution of the extracellular matrix (ECM) in decreasing the Lp by obtaining ECM after treatment of the monolayers with 0.025 M NH4OH to detach endothelial cells from the ECM. Basal ECM Lp (expressed x 10(-6) cm.s-1 x cmH2O-1) was 57.0 +/- 15.3, and it decreased to 19.7 +/- 4.3 and 17.5 +/- 2.9 during RCA and albumin, respectively (P < 0.01 for both). In contrast, RCA and albumin did not alter the filter Lp values. Another lectin, Ulex europaeus agglutinin, and the protein immunoglobulin G had no effect on Lp values.(ABSTRACT TRUNCATED AT 250 WORDS)
42
Drickamer, Kurt, and Andrew J. Fadden. "Genomic analysis of C-type lectins." Biochemical Society Symposia 69 (October 1, 2002): 59–72. http://dx.doi.org/10.1042/bss0690059.
Full textAbstract:
Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.
43
Asaga, H., and K. Yoshizato. "Recognition of collagen by fibroblasts through cell surface glycoproteins reactive with Phaseolus vulgaris agglutinin." Journal of Cell Science 101, no. 3 (March 1, 1992): 625–33. http://dx.doi.org/10.1242/jcs.101.3.625.
Full textAbstract:
The role of glycochains of cell surface glycoproteins in the cell to collagen interaction was examined by studying the effect of lectins on the fibroblast-mediated collagen gel contraction. Lectins of Phaseolus vulgaris agglutinin (PHA), concanavalin A (ConA), lentil seed agglutinin (LCA), pea agglutinin (PSA), Ricinus communis agglutinin-60 (RCA), and wheat germ agglutinin (WGA) dose-dependently inhibited gel contraction, while lectins of mushroom agglutinin (ABA), peanut agglutinin (PNA), pokeweed mitogen (PWM), and soybean agglutinin (SBA) did not. Of these lectins, PHA seemed to be worthy of further analysis, because PHA, but not other lectins, inhibited spreading of fibroblasts on collagen fibrils but not on plastic or gelatin, suggesting that cell-surface glycoproteins responsive to the lectin are involved in the specific binding of fibroblasts to native collagen fibrils. The inhibitory effect of PHA-E4, an isolectin of PHA, was more intense than that of PHA-L4, another isolectin of PHA. The collagen gel contraction was also inhibited by tunicamycin and monensin in a concentration-dependent and reversible manner. These results strongly suggest that PHA-E4-reactive glycoproteins of the fibroblast surface play an important role in cell to collagen binding during the gel contraction. Five membrane proteins including beta 1 subunits of the integrin family were obtained by affinity chromatography with PHA-E4.
44
Aring, Johannes, Jutta Schlepper-Schaefer, Volker Burkart, and Hubert Kolb. "Nonenzymatically glycated serum albumin: interaction with galactose-specific liver lectins." Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1010, no. 2 (February 1989): 140–44. http://dx.doi.org/10.1016/0167-4889(89)90153-5.
Full text
45
Wigglesworth-Cooksey, Barbara, and Keith E. Cooksey. "Use of Fluorophore-Conjugated Lectins To Study Cell-Cell Interactions in Model Marine Biofilms." Applied and Environmental Microbiology 71, no. 1 (January 2005): 428–35. http://dx.doi.org/10.1128/aem.71.1.428-435.2005.
Full textAbstract:
ABSTRACT Biofilms dominated by pennate diatoms are important in fields as diverse as ship biofouling and marine littoral sediment stabilization. The architecture of a biofilm depends on the fact that much of its mass consists of extracellular polymers. Although most illuminated biofilms in nature are dominated by phototrophs, they also contain heterotrophic bacteria. Given the close spatial association of the two types of organisms, cell-cell interaction is likely. Fluorophore-conjugated lectins were used to demonstrate the sites of the various extracellular polymers in three species of diatoms. Based on their lectin staining properties, the polymers in different species appeared to be similar, but their involvement in the process of attachment to a surface differed. In a coculture Pseudoalteromonas sp. strain 4 or its sterilized spent medium reduced the ability of Amphora coffeaeformis and Navicula sp. strains 1 and D to adhere, inhibited motility, and caused agglutination and eventually diatom cell lysis. Diatoms could be protected from the negative effects of the bacterial spent medium if d-galactose or mannan was included in the incubation medium. The active principle of the spent medium is probably a lectin/agglutinin that is able to bind to the extracellular polymers of the diatoms that are involved in adhesion and motility. Awareness of interactions of this type is important in the study of natural biofilms.
46
Cornish, Ann L., Sylvie Freeman, Gareth Forbes, Jian Ni, Mei Zhang, Mario Cepeda, Reiner Gentz, Meena Augustus, Kenneth C. Carter, and Paul R. Crocker. "Characterization of Siglec-5, a Novel Glycoprotein Expressed on Myeloid Cells Related to CD33." Blood 92, no. 6 (September 15, 1998): 2123–32. http://dx.doi.org/10.1182/blood.v92.6.2123.
Full textAbstract:
Abstract We describe the characterization of siglec-5 (sialic acid-binding Ig-like lectin-5), a novel transmembrane member of the immunoglobulin superfamily, highly related to the myeloid antigen, CD33. A full-length cDNA encoding siglec-5 was isolated from a human activated monocyte cDNA library. Sequencing predicted that siglec-5 contains four extracellular immunoglobulin-like domains, the N-terminal two of which are 57% identical to the corresponding region of CD33. The cytoplasmic tail is also related to that of CD33, containing two tyrosine residues embodied in immunoreceptor tyrosine-based inhibitory motif-like motifs. The siglec-5 gene was shown to map to chromosome 19q13.41-43, closely linked to the CD33 gene. When siglec-5 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG1, it was able to mediate sialic acid–dependent binding to human erythrocytes and soluble glycoconjugates, suggesting that it may be involved in cell-cell interactions. By using specific antibodies, siglec-5 was found to have an expression pattern distinct from that of CD33, being present at relatively high levels on neutrophils but absent from leukemic cell lines representing early stages of myelomonocytic differentiation. Western blot analysis of neutrophil lysates indicated that siglec-5 exists as a disulfide-linked dimer of approximately 140 kD. © 1998 by The American Society of Hematology.
47
Cornish, Ann L., Sylvie Freeman, Gareth Forbes, Jian Ni, Mei Zhang, Mario Cepeda, Reiner Gentz, Meena Augustus, Kenneth C. Carter, and Paul R. Crocker. "Characterization of Siglec-5, a Novel Glycoprotein Expressed on Myeloid Cells Related to CD33." Blood 92, no. 6 (September 15, 1998): 2123–32. http://dx.doi.org/10.1182/blood.v92.6.2123.418k20_2123_2132.
Full textAbstract:
We describe the characterization of siglec-5 (sialic acid-binding Ig-like lectin-5), a novel transmembrane member of the immunoglobulin superfamily, highly related to the myeloid antigen, CD33. A full-length cDNA encoding siglec-5 was isolated from a human activated monocyte cDNA library. Sequencing predicted that siglec-5 contains four extracellular immunoglobulin-like domains, the N-terminal two of which are 57% identical to the corresponding region of CD33. The cytoplasmic tail is also related to that of CD33, containing two tyrosine residues embodied in immunoreceptor tyrosine-based inhibitory motif-like motifs. The siglec-5 gene was shown to map to chromosome 19q13.41-43, closely linked to the CD33 gene. When siglec-5 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG1, it was able to mediate sialic acid–dependent binding to human erythrocytes and soluble glycoconjugates, suggesting that it may be involved in cell-cell interactions. By using specific antibodies, siglec-5 was found to have an expression pattern distinct from that of CD33, being present at relatively high levels on neutrophils but absent from leukemic cell lines representing early stages of myelomonocytic differentiation. Western blot analysis of neutrophil lysates indicated that siglec-5 exists as a disulfide-linked dimer of approximately 140 kD. © 1998 by The American Society of Hematology.
48
Naito-Matsui, Yuko, Shuhei Takada, Yoshinobu Kano, Tomonori Iyoda, Manabu Sugai, Akira Shimizu, Kayo Inaba, et al. "Functional Evaluation of Activation-dependent Alterations in the Sialoglycan Composition of T Cells." Journal of Biological Chemistry 289, no. 3 (December 2, 2013): 1564–79. http://dx.doi.org/10.1074/jbc.m113.523753.
Full textAbstract:
Sialic acids (Sias) are often conjugated to the termini of cellular glycans and are key mediators of cellular recognition. Sias are nine-carbon acidic sugars, and, in vertebrates, the major species are N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), differing in structure at the C5 position. Previously, we described a positive feedback loop involving regulation of Neu5Gc expression in mouse B cells. In this context, Neu5Gc negatively regulated B-cell proliferation, and Neu5Gc expression was suppressed upon activation. Similarly, resting mouse T cells expressed principally Neu5Gc, and Neu5Ac was induced upon activation. In the present work, we used various probes to examine sialoglycan expression by activated T cells in terms of the Sia species expressed and the linkages of Sias to glycans. Upon T-cell activation, sialoglycan expression shifted from Neu5Gc to Neu5Ac, and the linkage shifted from α2,6 to α2,3. These changes altered the expression levels of sialic acid-binding immunoglobulin-like lectin (siglec) ligands. Expression of sialoadhesin and Siglec-F ligands increased, and that of CD22 ligands decreased. Neu5Gc exerted a negative effect on T-cell activation, both in terms of the proliferative response and in the context of activation marker expression. Suppression of Neu5Gc expression in mouse T and B cells prevented the development of nonspecific CD22-mediated T cell-B cell interactions. Our results suggest that an activation-dependent shift from Neu5Gc to Neu5Ac and replacement of α2,6 by α2,3 linkages may regulate immune cell interactions at several levels.
49
Chopra, Martin, Andreas Brandl, Daniela Siegmund, Anja Mottok, Viktoria Schäfer, Marlene Biehl, Sabrina Kraus, et al. "Blocking TWEAK-Fn14 interaction inhibits hematopoietic stem cell transplantation-induced intestinal cell death and reduces GVHD." Blood 126, no. 4 (July 23, 2015): 437–44. http://dx.doi.org/10.1182/blood-2015-01-620583.
Full textAbstract:
Key Points Fn14 activation is involved in intestinal apoptosis after allo-HCT and contributes to gastrointestinal GVHD. Fn14 blockade with an ADCC-defective human immunoglobulin G1 antibody reduces GVHD severity without modulating GVL responses.
50
Tang, Jo Sing Julia, Sophia Rosencrantz, Lucas Tepper, Sany Chea, Stefanie Klöpzig, Anne Krüger-Genge, Joachim Storsberg, and Ruben R. Rosencrantz. "Functional Glyco-Nanogels for Multivalent Interaction with Lectins." Molecules 24, no. 10 (May 15, 2019): 1865. http://dx.doi.org/10.3390/molecules24101865.
Full textAbstract:
Interactions between glycans and proteins have tremendous impact in biomolecular interactions. They are important for cell–cell interactions, proliferation and much more. Here, we emphasize the glycan-mediated interactions between pathogens and host cells. Pseudomonas aeruginosa, responsible for a huge number of nosocomial infections, is especially the focus when it comes to glycan-derivatives as pathoblockers. We present a microwave assisted protecting group free synthesis of glycomonomers based on lactose, melibiose and fucose. The monomers were polymerized in a precipitation polymerization in the presence of NiPAm to form crosslinked glyco-nanogels. The influence of reaction parameters like crosslinker type or stabilizer amount was investigated. The gels were characterized in lectin binding studies using model lectins and showed size and composition-dependent inhibition of lectin binding. Due to multivalent presentation of glycans in the gel, the inhibition was clearly stronger than with unmodified saccharides, which was compared after determination of the glycan loading. First studies with Pseudomonas aeruginosa revealed a surprising influence on the secretion of virulence factors. Functional glycogels may be in the future potent alternatives or adjuvants for antibiotic treatment of infections based on glycan interactions between host and pathogen.