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Journal articles on the topic "Immune cell activation":
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Kerdiles, Yann, Sophie Ugolini, and Eric Vivier. "T cell regulation of natural killer cells." Journal of Experimental Medicine 210, no. 6 (June 3, 2013): 1065–68. http://dx.doi.org/10.1084/jem.20130960.
In light of their role in the immune response against tumors and viruses, natural killer (NK) cells represent a promising target for immunotherapy. Before this target is reached, the various mechanisms that control NK cell activity must first be identified and understood. In the past decades, studies have identified two critical processes that prevent spontaneous NK cell–mediated autoimmune activation while maximizing the efficiency of these cells during an immune response. First is the education process, whereby NK cells adapt to their environment by sensing ligands for inhibitory and activating receptors. Second is the priming phase of NK cell activation, which arms NK cells with appropriate cytotoxic molecules during inflammation. New studies now indicate that NK cell proliferation, accumulation, and activation are also under the control of regulatory T cells that restrict availability of IL-2 released by activated CD4+ T cells. Together with other recent studies, these data highlight the importance of the adaptive immune system in the regulation of NK cell activity.
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Ducloux, Didier, Jamal Bamoulid, Thomas Crepin, Jean-Michel Rebibou, Cecile Courivaud, and Philippe Saas. "Posttransplant Immune Activation." Cell Transplantation 26, no. 9 (September 2017): 1601–9. http://dx.doi.org/10.1177/0963689717735404.
Cardiovascular disease is a major cause of morbidity, disability, and mortality in kidney transplant patients. Cumulative reports indicate that the excessive risk of cardiovascular events is not entirely explained by the increased prevalence of traditional cardiovascular risk factors. Atherosclerosis is a chronic inflammatory disease, and it has been postulated that posttransplant immune disturbances may explain the gap between the predicted and observed risks of cardiovascular events. Although concordant data suggest that innate immunity contributes to the posttransplant accelerated atherosclerosis, only few arguments plead for a role of adaptive immunity. We report and discuss here consistent data demonstrating that CD8+ T cell activation is a frequent posttransplant immune feature that may have pro-atherogenic effects. Expansion of exhausted/activated CD8+ T cells in kidney transplant recipients is stimulated by several factors including cytomegalovirus infections, lymphodepletive therapy (e.g., antithymocyte globulins), chronic allogeneic stimulation, and a past history of renal insufficiency. This is observed in the setting of decreased thymic activity, a process also found in elderly individuals and reflecting accelerated immune senescence.
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Čemerski, Sašo, and Andrey Shaw. "Immune synapses in T-cell activation." Current Opinion in Immunology 18, no. 3 (June 2006): 298–304. http://dx.doi.org/10.1016/j.coi.2006.03.011.
Since ferroptosis, a form of cell death characterized by aberrant lipid peroxidation, was proposed 10 years ago, its interaction with the immune system has been revealed gradually. On the one hand, immune cell-secreted cytokines are able to increase or suppress ferroptosis sensitivities of other cell types, such as tumor cells and fibroblasts. On the other hand, ferroptotic cell-released factors have the capacity to modulate the functions of neighboring immune cells, including dendritic cells, macrophages, and T cells. Identifying these immunomodulatory molecules generated during ferroptosis paves the way for developing novel immunotherapy strategies for treating cancer and autoimmune diseases.
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Kowalska-Kępczyńska, Anna, Mateusz Mleczko, Weronika Domerecka, Dorota Krasowska, and Helena Donica. "Assessment of Immune Cell Activation in Pemphigus." Cells 11, no. 12 (June 13, 2022): 1912. http://dx.doi.org/10.3390/cells11121912.
(1) Background: Pemphigus is a blistering autoimmune disease of the skin and/or mucous membranes, characterised by the presence of specific autoantibodies directed against structural proteins of the human skin. Recent reports indicate that new haematological parameters, termed Extended Inflammation Parameters (EIP), can be used to assess the activation of immune cells during active inflammation. These include parameters assessing both neutrophil activation (NEUT-RI, NEUT-GI) and the number of activated lymphocytes (RE-LYMP). The aim of this study was to investigate the relationship between changes in NEUT-RI, NEUT-GI and RE-LYMP and the disease activity in patients with pemphigus. (2) Results: The study involved 32 patients with diagnosed different types of pemphigus. Neutrophil activation parameters (NEUT-RI and NEUT-GI) and lymphocytes (RE-LYMP) were significantly higher in these patients compared to the parameters in healthy participants (respectively p = 0.0127, p = 0.0011 and p = 0.0033). The increased quantity of activated lymphocytes (RE-LYMP) also correlated significantly with the extent of skin and/or mucosal lesions in patients assessed by the PDAI scale (p < 0.02). (3) Conclusions: The NEUT-RI, NEUT-GI and RE-LYMP parameters proved to be appropriate markers of inflammation severity in pemphigus, also in relation to local lesions, which was not possible with the inflammation markers (CRP, ESR) used so far on a routine basis.
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Roberts, Rebecca, Henry Leonard, Ilona Aylott, Douglas Best, Dan Rocca, Ben Thompson, Nunan Robert, and Louise Brackenbury. "Abstract 1844: Development of a high content screening (HCS) platform for novel cancer immunotherapeutics." Cancer Research 83, no. 7_Supplement (April 4, 2023): 1844. http://dx.doi.org/10.1158/1538-7445.am2023-1844.
Abstract There has been dramatic progress in the understanding of fundamental causes of cancer, giving rise to novel treatments which harness the power of the immune system to combat cancer progression. Despite this, no two cancers have the same pathogenesis and there is significant variation in patient response rates. Understanding mechanisms of carcinogenesis in model cell culture systems, such as aberrant signaling, as well as how tumor immunity can be initiated, retargeted or reinvigorated upon incorporation of the immune system will fuel drug discovery. High-Content Screening (HCS) platforms allow single-cell imaging analysis and are used to interrogate these models to enable drug development and understand mechanisms of action. They provide an opportunity to test novel cancer therapeutics in a translationally relevant setting that integrates primary immune effector function. Here we outline several macrophage-based HCS assays which allow assessment of therapeutics targeting;1) early aspects of immune cell activation 2) macrophage mitochondrial health 3) macrophage activation and re-polarization 4) immune cell infiltration and tumor killing. To test efficacy of drugs targeting immune signaling or activation, macrophages were treated with a canonical NF-ƙB activator +/- TCPA-1, a known inhibitor for benchmarking as a model therapeutic. Robust NF-ƙB translocation was observed and reduced in the presence of TCPA-1 rendering this an appropriate assay to screen therapeutic cytokines or TLR agonists activating NF-ƙB signaling. A macrophage inflammasome activation assay was developed to analyze levels of ASC and speck formation. CRID3i, an established inflammasome inhibitor was validated as a robust control therapeutic that prevented NLRP3 activation suggesting this is a relevant platform to assess cancer drug efficacy. Interrogating mitochondrial health and dynamics in primary macrophages is vital to understanding the impact of accumulating ROS species or metabolites in the tumor microenvironment. Assays modelling the effects of these molecules on macrophage polarization and activation as well as mitochondrial integrity were used to test macrophage repolarizing therapeutics, a key approach in immuno-oncology. Finally, a complex multi-cellular 3D spheroid tumor killing assay was optimized to model immune cell infiltration following exposure to IO-targeted therapeutics and robust enhancement of tumor killing was directly observed. Overall, these assays demonstrate the power of imaging in performing HCS to assess the efficacy and mechanisms of action of a range of IO-targeted therapeutics. This suite of assays is applicable to IO drug screens targeting macrophage function, immune cell activation and immune cell infiltration. Citation Format: Rebecca Roberts, Henry Leonard, Ilona Aylott, Douglas Best, Dan Rocca, Ben Thompson, Nunan Robert, Louise Brackenbury. Development of a high content screening (HCS) platform for novel cancer immunotherapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1844.
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Haque, Mohammad, Safnas Abdul Salam, Shawn McGinley, Haiching Ma, and jianghong Wu. "Abstract 6650: Cell-based assay to support development and characterization of new drugs in immuno-oncology." Cancer Research 83, no. 7_Supplement (April 4, 2023): 6650. http://dx.doi.org/10.1158/1538-7445.am2023-6650.
Abstract The years since 2009 have seen tremendous progress in unlocking the curative potential of the immune system for the treatment of cancer. Much of that revolution in immuno-oncology has been fueled by the clinical success of immune checkpoint inhibitors, targeting cytokines, antibody dependent cell cytotoxicity and complement dependent cytotoxicity via the T cell activation. Reaction biology has established state-of-art high throughput screening procedures for measuring the ability of new Biologics or compounds to activate T cells. Antibody Dependent Cell Cytotoxicity (ADCC), T cell activation assay (NFAT), immune checkpoint inhibitor assay (PD-1/PD-L1 blockade bioassay), cytokines activation assay and Complement Dependent Cytotoxicity (CDC) are commonly used for drug discovery industry. ADCC is a desirable mechanism for killing target cells using antibody-based drugs. T cell activation assay can be used for the discovery and development of novel biologics and cell therapies aimed at inducing, strengthening and/or engineering T cell response. Blocking of immune inhibitory receptors by their respective ligands on an adjacent cell inhibits TCR mediated proliferation, transcriptional activation and cytokines production. Biologics or compounds designed for measuring the stimulatory or inhibitory function of cytokines are promising in the field of immune oncology. Reaction Biology developed biochemical assays for PD-1/PD-L1, CTLA4/CD80 and CTLA4/CD86 to screen immune checkpoint inhibitors. All of these screening procedures and experimental methods will help to identify new therapeutic biologics or compounds for drug discovery in immune-oncology field. Citation Format: Mohammad Haque, Safnas Abdul Salam, Shawn McGinley, Haiching Ma, jianghong Wu. Cell-based assay to support development and characterization of new drugs in immuno-oncology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6650.
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Saunders, Ute, and John F. Kearney. "Exosome-mediated B cell activation (36.11)." Journal of Immunology 178, no. 1_Supplement (April 1, 2007): S14. http://dx.doi.org/10.4049/jimmunol.178.supp.36.11.
Abstract The mature B cell population is divided into splenic follicular (FO) B, marginal zone (MZ) B and B1 B cells by phenotype, localization, and function. MZ B and B1 B cells participate in the early immune response against blood-borne T-independent (TI) antigens to bridge the temporal gap between the innate and adaptive immune response. We previously described the capture and transport of bacteria to the spleen by blood-derived CD11c immature dendritic cells (DCs), which are responsible for initiating immune responses to TI-2 antigens. However, the molecular basis of the DC-B cell interaction is complex, since supernatant (SN) from bacteria-primed DCs alone initiates antigen (Ag)-specific MZ B cell differentiation in vitro. Therefore, we propose that bacteria-primed DCs release factors able to initiate Ag-specific plasmablast generation. Recent findings that DCs secrete exosomes, which have the ability to stimulate T-dependent (TD) immune responses, support our hypothesis. To determine whether exosomes are involved in TI immune responses, we isolated exosomes from SN of bacteria-primed DCs (BMDC) and cocultured them with splenic B cells from M167 heavy chain transgenic (tg) mice expressing a dominant B cell clone, reactive with phosphorylcholine (PC). Using this system, we show that exosomes isolated from SN of Streptococcus pneumoniae primed BMDCs can specifically activate the M167 B cell clones, but not B cells from hen-egg-lysozyme (HEL)-specific MD4 tg B cell mice. These results suggest an involvement of exosomes in Ag-specific MZ B cell differentiation.
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Trott, Daniel W., and David G. Harrison. "The immune system in hypertension." Advances in Physiology Education 38, no. 1 (March 2014): 20–24. http://dx.doi.org/10.1152/advan.00063.2013.
While hypertension has predominantly been attributed to perturbations of the vasculature, kidney, and central nervous system, research for almost 50 yr has shown that the immune system also contributes to this disease. Inflammatory cells accumulate in the kidneys and vasculature of humans and experimental animals with hypertension and likely contribute to end-organ damage. We and others have shown that mice lacking adaptive immune cells, including recombinase-activating gene-deficient mice and rats and mice with severe combined immunodeficiency have blunted hypertension to stimuli such as ANG II, high salt, and norepinephrine. Adoptive transfer of T cells restores the blood pressure response to these stimuli. Agonistic antibodies to the ANG II receptor, produced by B cells, contribute to hypertension in experimental models of preeclampsia. The central nervous system seems important in immune cell activation, because lesions in the anteroventral third ventricle block hypertension and T cell activation in response to ANG II. Likewise, genetic manipulation of reactive oxygen species in the subfornical organ modulates both hypertension and immune cell activation. Current evidence indicates that the production of cytokines, including tumor necrosis factor-α, interleukin-17, and interleukin-6, contribute to hypertension, likely via effects on both the kidney and vasculature. In addition, the innate immune system also appears to contribute to hypertension. We propose a working hypothesis linking the sympathetic nervous system, immune cells, production of cytokines, and, ultimately, vascular and renal dysfunction, leading to the augmentation of hypertension. Studies of immune cell activation will clearly be useful in understanding this common yet complex disease.
This thesis describes the fabrication of biomimetic substrates, and their use as tools to probe cellular interactions of key immune cells. Nanoparticles of gold and zinc sulfide have been fabricated, and patterned into nanoarrays. Adaptive (T cell) and innate (NK cell) immune cell responses to nanoscale spacing of ligand-receptor pairs were measured, and the effect of presenting stimulatory ligands on substrates with varying mechanical properties has been tested for T cell responses. The advanced materials in this thesis act to create artificial immune synapses, and probe the effect of these stimuli on engagement and activation of human immune cells. Specifically, block co-polymers were used to form polymer micelles which encapsulate metal ions and form metal or metal compound nanoparticles. Micelles encapsulating metal ions or nanoparticles were formed and deposited onto substrates using Block Co-polymer Micellar Lithography (BCML) to form nanoparticle arrays with controlled inter-particle spacing. Well controlled gold nanoparticle arrays with spacing between 25-150nm have been produced. The technique has been further developed to include fabrication of zinc sulfide particles and nanoarrays. Zinc sulfide nanoparticles showed a unique internal structure with 5nm crystalline domains set in an amorphous matrix and an optical band gap of between 3.88-4.28eV. Nanoparticle arrays were then functionalised with biological ligands, notably antibodies that engage with the NK cell surface receptor CD16, or the T cell TCR/CD3 moiety. The cellular response to these materials was measured, and was sensitive to the nanoscale arrangement of stimulatory ligands; both cell types responded to ligands with 25nm, but not 104nm, inter-ligand spacing. In an alternative approach, spherical PEG hydrogel particles of diameter 5-50μm were formed with controlled rigidity between 3-2000kPa. T cell response as a function of substrate rigidity was tested, and cells showed maximal response to anti-CD3 functionalised substrates with rigidities of 3-5kPa.
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Tilney-Bassett, Amanda L. "Phospholipid metabolism in T-cell activation." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239331.
Cliff, Jacqueline Margaret. "The role of autocrine factors in B cell activation." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327054.
Embryonic stem cells (ESC) possess immune privileged properties and have the capacity to modulate immune activation. ESCs can persist across allogeneic immunological barriers, prevent lymphocyte proliferation in mixed lymphocyte reaction (MLR) assays and can promote graft acceptance. However, clinical application of live ESC to treat immunological disorders is not feasible as live ESC can form teratoma in-vivo. In order to harness these properties of ESCs without adverse risk to patients, we hypothesized that ESC derived extracts may retain immune modulatory properties of whole cells and therefore could be used to abrogate allo-immune responses. We found addition of ESC-extracts from human lines H1 and H9, significantly prevented T cell proliferation in allogeneic MLRs. These results were confirmed using murine J1 ESC line. In-vitro studies showed human ESC EXT were able to modulate maturation of human monocyte derived dendritic cells (DC) by suppressing up-regulation of important co-stimulatory and maturation markers CD80, HLA-DR and CD83. In addition, DCs educated in the presence of human ESC extracts significantly lost their ability to stimulate purified allogeneic T cells compared to control extract treated DCs. We also determined that ESC extracts have an independent effect on T cells. ESC extracts prevented T cell proliferation in response to anti CD3/CD28 stimulation. In MLRs, ESC derived factors significantly down-regulated IL-2 and IFN-γ expression, while up-regulating TGF-β and Foxp3 expression. Furthermore, lymphocytes and purified T cells activated with anti-CD3/CD28, ConA and PMA proliferated poorly in the presence of ESC derived factors, while proliferation in response to ionomycin was not affected. Western blot analysis indicated that ESC derived factors prevented PKC-θ phosphorylation without influencing total PKC-θ levels. Moreover, IκB-α degradation was abrogated, confirming absence of PKC-θ activity. Therefore, ESC extracts have potent immune suppressive properties and may have clinical applications in ameliorating transplant rejection and autoimmune conditions.
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Nugent, Alexandria Lynne. "Morphine activation of stress pathways alters peripheral immune cell signaling." Connect to Electronic Thesis (ProQuest), 2008. http://0-gateway.proquest.com.library.lausys.georgetown.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3315451.
Nyambuya, Tawanda Maurice. "Markers of chronic immune activation and T-cell function in hyperglycaemia." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2597.
Thesis (MTech (Biomedical Sciences))--Cape Peninsula University of Technology, 2017. Type 2 diabetes mellitus (T2DM) is a chronic inflammatory condition characterised by hyperglycaemia; continuous activation of T-lymphocytes and immune dysregulation. Although the exact mechanisms of these phenomena are not fully understood, there is strong evidence suggesting the involvement of T-cells in the chronic inflammatory environment which could predispose diabetics to infections and thrombotic events. The effect of hyperglycaemia on cells of the innate immune system in T2DM has been well described and implicated in the progression of the disorder and the development of its complications. However, studies investigating the adaptive immune response still remain scarce and controversial. Thus, investigating T-cells in hyperglycaemic conditions could provide further insight into the immune dysfunction observed in T2DM and assist in identifying pathways which could be targeted in the disease management and treatment. Therefore, this study aimed to investigate chronic immune activation by measuring the expression of T-cell activation markers in hyperglycaemia and compare the results to those in the normoglycaemic group.
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Clary, Sara Reed. "The effects of nitrosoureas on Thymocyte differentiation and T cell activation." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41939.
Cantrell, Jessica. "Adjuvant Effect of Chaperone-Rich Cell Lysate: The Effects of CRCL on the Activation of Immune Cells." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195380.
Cancer immunotherapy aims to use and manipulate the host’s immune system to fight against cancer. The objective of this strategy is to induce specific and persistent immune responses leading to tumor eradication. Heat shock proteins (HSP) purified from cancer tissues have been identified as unique mediators of specific anti-tumor immunity. In our laboratory, we have developed an original vaccine, termed CRCL (Chaperone-Rich Cell Lysate) that consists of multiple HSP complexes enriched from tumor lysates. CRCL immunization leads to an efficient protection against a wide variety of murine cancers by inducing a strong, long-lasting, and specific T and NK-cell dependent immune responses against the tumor from which it has been generated. Tumor-derived CRCL has been shown to be more efficient in triggering DC activation than individual purified HSP or tumor lysates. The immunostimulatory effects of CRCL arise from its superior ability to provide a wide variety of tumor antigens to the immune system and by providing potent adjuvant effects. However, CD4⁺CD25⁺ regulatory T lymphocytes (Treg) critically contribute to the mechanisms of cancer-induced suppression. Data from independent groups including ours suggests they may also restrain the function of antigen presenting cells. The current study was designed to elucidate the molecular signaling events triggered by the tumor-derived CRCL vaccine in antigen presenting cells and evaluate whether CRCL may overcome the inhibitory effects of Treg modulation of DC and macrophage activation. Our results indicate CRCL activates DC and macrophages by inducing proinflammatory cytokine chemokine secretion. CRCL induces iNOS expression and NO production in macrophages. CRCL activation of DC and macrophages results in transcription factor NF-κB activation in vitro and in vivo, and this includes the activation of additional signaling molecules upstream of NF-κB. Following CRCL treatment the phenotypic maturation of DC, the production of DC and macrophage pro-inflammatory cytokines, and the activation of the transcription factor NF-κB are not affected by Treg. Additionally, CRCL induced activation of DC is not diminished by the immunosuppressive cytokine TGF-β 1. Our results indicate tumor-derived CRCL-treated DC and macrophages are refractory to Treg inhibition. These results are important for advancing CRCL-based vaccines in Phase I clinical trials.
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Taner, Sabrina Beliz. "The role of lipid rafts in natural killer cell activation and immune surveillance." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423546.
Carlin, Lindsey Elizabeth. "Natural killer cell activation, trafficking, and contribution to immune responses to viral pathogens." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1302.
Natural killer (NK) cells are a critical component of the immune response against viral infections. NK cell depletion prior to murine cytomegalovirus (MCMV) infections results in increased susceptibility to infection in several mouse strains. The mechanism of protection in C57Bl/6 mice is dependent on the activation of NK cells by Ly49H recognition of m157. Our previous studies have examined important residues of m157 for Ly49H recognition, as well as the contribution of m157 glycosylation to NK cell activation. However, what role the glycophosphatidyl inositol (GPI) anchor of m157 plays in Ly49H activation was unknown. Here we demonstrate that the GPI anchor of m157 regulates the surface expression of the protein. While the GPI anchor was not required for recognition of m157 by the activating or inhibitory Ly49 receptors, expression of GPI-anchored m157 resulted in greater receptor downregulation on NK cells, as well as increased NK cell cytotoxicity compared to transmembrane m157.
In addition to MCMV infections, NK cells have been shown to participate in the immune response to influenza A virus (IAV). However the exact role of NK cells in IAV infection is less clear, as some studies have found NK cells to be protective, while others have shown that NK cells cause lethal immunopathology. It is likely that the severity of IAV infection may dictate the NK cell response to IAV infection (i.e. protective vs. immunopathogenic). Herein we show that NK cell accumulation in IAV-infected lungs and lung-draining lymph nodes (DLN) is regulated by the severity of IAV infection, where there is increased NK cell accumulation in the lungs during high dose IAV infection, and greater NK cell accumulation in the DLN in low dose IAV infections. Despite significant NK cell recruitment to the lung during IAV infection, as well as previously published studies demonstrating the importance of NK cells to IAV immunity, NK cell depletion prior to IAV infection did not result in a significant change in morbidity or mortality. Interestingly, NK cell depletion resulted in a significantly greater number of CD4 T cells in the IAV infected lung. Further, both CD4 and CD8 T cells in NK-depleted mice showed increased IFN-Γ production. Finally, while not statistically significant, NK cell depletion resulted in a trend toward greater protection from heterosubtypic IAV challenge infections. Taken together these results suggest that NK cells may either regulate the adaptive immune response to IAV infection through suppression of CD4 and CD8 T cells, or that the T cell response to IAV infection is able to compensate for the loss of NK cells. Moreover, while NK cell suppression of T cell function during a primary IAV infection does not result in increased susceptibility to primary IAV infections, NK cell regulation of adaptive immune responses may suppress the memory T cell response, and therefore leave the host more susceptible to secondary infections.
Overall the studies presented herein demonstrate a complex role for NK cells in the immune response against viral infections. Ly49H+ NK cells directly kill MCMV-infected cells and m157-bearing targets, but NK cell activation is regulated by ligand density, as well as the ligand membrane anchor. Additionally, NK cells suppress adaptive immune responses during a primary IAV infection, resulting in changes to the T cell response during both primary and memory responses.
International Conference on B Cell Biology (11th 2006 Newport Beach, Calif.). Mechanisms of lymphocyte activation and immune regulation XI: B cell biology. New York: Springer, 2007.
International Conference on Lymphocyte Activation and Immune Regulation (9th 2002 Newport Beach, Calif.). Lymphocyte activation and immune regulation IX: Homeostasis and lymphocyte traffic. New York: Kluwer Academic/Plenum Publishers, 2002.
Sudhir, Gupta, and International Conference on Mechanisms of Lymphocyte Activation and Immune Regulation (5th : 1994 : Newport Beach, Calif.), eds. Mechanisms of lymphocyte activation and immune regulation V: Molecular basis of signal transduction. New York: Plenum Press, 1994.
Miami Bio/Technology Winter Symposium (1990 Miami, Fla.). Advances in gene technology: The molecular biology of immune diseases and the immune reponse : proceedings of the 1990 Miami Bio/Technology Winter Symposia. Oxford: IRL Press, 1990.
Marc, Feldmann, Maini R. N, Woody James N, and United States. Naval Medical Research and Development Command., eds. T-cell activation in health and disease: Disorders of immune regulation infection and autoimmunity : papers from an international meeting in Oxford, UK, in September 1988. London ; San Diego: Academic Press, 1989.
International Conference on Lymphocyte Activation and Immune Regulation (1986 Newport Beach, Calif.). Mechanisms of lymphocyte activation and immune regulation. New York: Plenum Press, 1987.
International Conference on Lymphocyte Activation and Immune Regulation (1986 Newport Beach, Calif.). Mechanisms of lymphocyte activation and immune regulation. New York: Plenum Press, 1987.
International Conference on Lymphocyte Activation and Immune Regulation (9th 2002 Newport Beach, Calif.). Lymphocyte activation and immune regulation IX: Homeostasis and lymphocyte traffic. New York: Kluwer Academic/Plenum Publishers, 2002.
Book chapters on the topic "Immune cell activation":
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Schimpl, A., and R. B. Corley. "Signals in B Cell Activation." In Immune Regulation, 61–64. Totowa, NJ: Humana Press, 1985. http://dx.doi.org/10.1007/978-1-4612-4996-2_6.
Charron, Dominique J., and Michaël J. Crumpton. "Receptors Involved in T Cell Activation." In Immune Regulation, 151–55. Totowa, NJ: Humana Press, 1985. http://dx.doi.org/10.1007/978-1-4612-4996-2_20.
Holler, Ernst, Hildegard Greinix, and Robert Zeiser. "Acute Graft-Versus-Host Disease." In The EBMT Handbook, 385–93. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-44080-9_43.
AbstractAcute graft-versus-host disease (GvHD) remains a major course of short term (100 days and 1 yr) mortality and morbidity after allogeneic stem cell transplantation. The pathophysiology of GvHD is described as a 3 step process starting with initial tissue damage by conditioning followed by host antigen presenting cell activation by damage and pathogen associated molecular patterns and finally resulting in activation of alloreactive T cells and proinflmmatory cytokines inducing target cell apoptosis. This activating cycle elicits multiple regulatory mechanisms and cells such as regulatory T cells and myeloid derived suppressor cells. Besides the disturbed balance between immune activation and immune tolerance, a disturbed capacity of tissue repair contributes to clincal damage.
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Ambrus, Julian L., and Anthony S. Fauci. "The Human B Cell Cycle: Activation, Proliferation, and Differentiation." In Immune Regulation, 101–9. Totowa, NJ: Humana Press, 1985. http://dx.doi.org/10.1007/978-1-4612-4996-2_13.
Müller, Sabina, Liza Filali, Marie-Pierre Puissegur, and Salvatore Valitutti. "Measuring CTL Lytic Granule Secretion and Target Cell Membrane Repair by Fluorescent Lipophilic Dye Uptake at the Lytic Synapse." In The Immune Synapse, 463–76. New York, NY: Springer US, 2023. http://dx.doi.org/10.1007/978-1-0716-3135-5_30.
AbstractCD8+ cytotoxic T lymphocytes (CTL) play a key role in anti-tumor immune response. They are therefore at the heart of current immunotherapy protocols against cancer. Despite current strategies to potentiate CTL responses, cancer cells can resist CTL attack, thus limiting the efficacy of immunotherapies. To optimize immunotherapy, it is urgent to develop rapid assays allowing to assess CTL-cancer cell confrontation at the lytic synapse.In this chapter, we describe a flow cytometry-based method to simultaneously assess the extent of CTL activation and of tumor cell reparative membrane turnover in CTL/target cell conjugates. Such a method can be performed using a limited number of cells. It can therefore be employed in clinical settings when only a few patient-derived cells might be available.
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Davis, M. M., N. R. J. Gascoigne, T. Lindsten, C. Goodnow, and Y. Chien. "Murine T-Cell Receptor Genes." In Mechanisms of Lymphocyte Activation and Immune Regulation, 13–17. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5323-2_2.
Swain, Susan L., and Richard W. Dutton. "B Cell Growth Factor Interactions." In Mechanisms of Lymphocyte Activation and Immune Regulation, 215–25. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5323-2_21.
Neves, Bruno M., and Catarina R. Almeida. "Signaling Pathways Governing Activation of Innate Immune Cells." In Tissue-Specific Cell Signaling, 93–131. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44436-5_4.
Mollenhauer, Martin, and Anna Klinke. "Myeloperoxidase and Immune Cell Recruitment and Activation." In Mammalian Heme Peroxidases, 153–70. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003212287-12.
Olive, D., P. Dubreuil, D. Charmot, C. Mawas, and P. Mannoni. "T Cell Activation Antigens: Kinetics, Tissue Distribution, Molecular Weights, and Functions; Induction on Non T Cell Lines by Lymphokines." In Immune Regulation, 39–50. Totowa, NJ: Humana Press, 1985. http://dx.doi.org/10.1007/978-1-4612-4996-2_4.
Conference papers on the topic "Immune cell activation":
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Zhao, Yu, Nikolaos I. Kanellakis, Yanchun Peng, Beibei Wang, Adan Pinto Fernandez, Megat Bin Abd Hamid, Xuan Yao, et al. "Dactinomycin could prime immune cell therapy via activation of tumour cell STING." In ERS International Congress 2023 abstracts. European Respiratory Society, 2023. http://dx.doi.org/10.1183/13993003.congress-2023.pa3435.
Wu, Eric, Aaron Mayer, Alexandro E. Trevino, and James Zou. "1314 Polarity measurements from multiplex imaging suggest immune cell activation." In SITC 38th Annual Meeting (SITC 2023) Abstracts. BMJ Publishing Group Ltd, 2023. http://dx.doi.org/10.1136/jitc-2023-sitc2023.1314.
Kooistra, T., A. Pardo-Saganta, K. Discipio, J. Gillis, J. L. Cho, J. Rajagopal, and B. D. Medoff. "Airway Basal Cell Notch Signaling Coordinates Immune Cell Localization and Activation in Asthma." In American Thoracic Society 2019 International Conference, May 17-22, 2019 - Dallas, TX. American Thoracic Society, 2019. http://dx.doi.org/10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a5556.
Frolova, A. A., M. R. Patysheva, A. A. Fedorov, M. A. Vostrikova, O. D. Bragina, V. Yu Korobeynikov, T. S. Gerashchenko, and N. V. Cherdyntseva. "SINGLE-CELL IMMUNE PROFILING OF BREAST CANCER PATIENTS UNDER CHEMOTHERAPY." In X Международная конференция молодых ученых: биоинформатиков, биотехнологов, биофизиков, вирусологов и молекулярных биологов — 2023. Novosibirsk State University, 2023. http://dx.doi.org/10.25205/978-5-4437-1526-1-384.
The main method of TNBC systemic treatment is chemotherapy. In this work, the immune landscape of the blood of patients with TNBC was evaluated using single cell sequencing technology in the dynamics of neoadjuvant chemotherapy. It has been shown that under the influence of therapy, dynamic changes in the population composition occur, leading to the activation of the adaptive immune response.
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Schaller, Teilo H., Kristen A. Batich, Kelly Hotchkiss, Xiuyu Cui, Luis Sanchez-Perez, and John H. Sampson. "Abstract A80: The effects of CCL3 on dendritic cell migration and immune cell activation." In Abstracts: AACR Special Conference on Tumor Immunology and Immunotherapy; November 27-30, 2018; Miami Beach, FL. American Association for Cancer Research, 2020. http://dx.doi.org/10.1158/2326-6074.tumimm18-a80.
Bevan, Nicola, Hinnah Campwala, Clare Szybut, Kalpana Patel, Dan Appledorn, Tim Dale, and Derek Trezise. "Abstract 4011: Validation of novel continuous live-cell assays for immune cell activation and killing of blood cell cancers." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-4011.
Liu, Xiao-Ling. "DECIPHERING THE GENETIC LINKS BETWEEN PSYCHOLOGICAL STRESS, AUTOPHAGY, AND DERMATOLOGICAL HEALTH: INSIGHTS FROM BIOINFORMATICS, SINGLE-CELL ANALYSIS, AND MACHINE LEARNING IN PSORIASIS AND ANXIETY DISORDERS." In BioClina 2024 – International Conference on Biological & Clinical Studies, 21-22 June, Singapore. Global Research & Development Services, 2024. http://dx.doi.org/10.20319/icrlsh.2024.8687.
The relationship between psychological stress, altered skin immunity, and autophagy-related genes (ATGs) is currently unclear. Psoriasis is a chronic skin inflammation of unclear etiology that is characterized by persistence and recurrence. Immune dysregulation and emotional disturbances are recognized as significant risk factors. Emerging clinical evidence suggests a possible connection between anxiety disorders, heightened immune system activation, and altered skin immunity, offering a fresh perspective on the initiation of psoriasis. The aim of this study was to explore the potential shared biological mechanisms underlying the comorbidity of psoriasis and anxiety disorders. Psoriasis and anxiety disorders data were obtained from the GEO database. A list of 3254 ATGs was obtained from the public database. Differentially expressed genes (DEGs) were obtained by taking the intersection of DEGs between psoriasis and anxiety disorder samples and the list of ATGs. Five machine learning algorithms used screening hub genes. The ROC curve was performed to evaluate diagnostic performance. Then, GSEA, immune infiltration analysis, and network analysis were carried out. The Seurat and Monocle algorithms were used to depict T-cell evolution. Cellchat was used to infer the signaling pathway between keratinocytes and immune cells. Four key hub genes were identified as diagnostic genes related to psoriasis autophagy. Enrichment analysis showed that these genes are indeed related to T cells, autophagy, and immune regulation, and have good diagnostic efficacy validated. Using single-cell RNA sequencing analysis, we expanded our understanding of key cellular participants, including inflammatory keratinocytes and their interactions with immune cells. We found that the CASP7 gene is involved in the T-cell development process, and correlated with γδ T cells, warranting further investigation. We found that anxiety disorders are related to increased autophagy regulation, immune dysregulation, and inflammatory response, and are reflected in the onset and exacerbation of skin inflammation. The hub gene is involved in the process of immune signaling and immune regulation. The CASP7 gene, which is related with the development and differentiation of T cells, deserves further study. Potential biomarkers between psoriasis and anxiety disorders were identified, which are expected to aid in the prediction of disease diagnosis and the development of personalized treatments.
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Zhang, Tong, Jing Song, Yucheng Li, Jie Ma, Yingdi Shi, Xiaoran Wu, Lanlan Xu, et al. "Abstract 2226: Anti-human PD-1 antibody BGB-A317 exhibits potent immune cell activation." In Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-2226.
Rangamuwa, K., M. Christie, T. Leong, C. Aloe, K. Yokote, D. Batey, M. L. Asselin-Labat, et al. "Anti-cancer Immune Activation Post Bronchoscopic Thermal Ablation in Non-small Cell Lung Cancer." In American Thoracic Society 2024 International Conference, May 17-22, 2024 - San Diego, CA. American Thoracic Society, 2024. http://dx.doi.org/10.1164/ajrccm-conference.2024.209.1_meetingabstracts.a6977.
de Cubas, Aguirre A., William Dunker, Rachel Hongo, Anuj Bhatia, Andrew Zaninovich, Anshuman Panda, Kathryn E. Beckermann, et al. "Abstract 4495: DNA demethylation promotes ERV expression and activation of immune signaling in renal cell cancer cells." In Proceedings: AACR Annual Meeting 2020; April 27-28, 2020 and June 22-24, 2020; Philadelphia, PA. American Association for Cancer Research, 2020. http://dx.doi.org/10.1158/1538-7445.am2020-4495.
Evans, Donald L., Avigdor Eldar, Liliana Jaso-Friedmann, and Herve Bercovier. Streptococcus Iniae Infection in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Towards the Pathogen and Vaccine Formulation. United States Department of Agriculture, February 2005. http://dx.doi.org/10.32747/2005.7586538.bard.
The objectives of the BARD proposal were to determine the mechanisms of nonspecific cytotoxic cells (NCC) that are necessary to provide heightened innate resistance to infection and to identify the antigenic determinants in Streptococcus iniae that are best suited for vaccine development. Our central hypothesis was that anti-bacterial immunity in trout and tilapia can only be acquired by combining "innate" NCC responses with antibody responses to polysaccharide antigens. These Objectives were accomplished by experiments delineated by the following Specific Aims: Specific aim (SA) #1 (USA) "Clone and Identify the Apoptosis Regulatory Genes in NCC"; Specific aim #2 (USA)"Identify Regulatory Factors that Control NCC Responses to S. iniae"; Specific aim #3 (Israel) "Characterize the Biological Properties of the S. iniae Capsular Polysaccharide"; and Specific aim #4 (Israel) "Development of an Acellular Vaccine". Our model of S. iniae pathogenesis encompassed two approaches, identify apoptosis regulatory genes and proteins in tilapia that affected NCC activities (USA group) and determine the participation of S.iniae capsular polysaccharides as potential immunogens for the development of an acellular vaccine (Israel group). We previously established that it was possible to immunize tilapia and trout against experimental S. difficile/iniaeinfections. However these studies indicated that antibody responses in protected fish were short lived (3-4 months). Thus available vaccines were useful for short-term protection only. To address the issues of regulation of pathogenesis and immunogens of S. iniae, we have emphasized the role of the innate immune response regarding activation of NCC and mechanisms of invasiveness. Considerable progress was made toward accomplishing SA #1. We have cloned the cDNA of the following tilapia genes: cellular apoptosis susceptibility (CAS/AF547173»; tumor necrosis factor alpha (TNF / A Y 428948); and nascent polypeptide-associated complex alpha polypeptide (NACA/ A Y168640). Similar attempts were made to sequence the tilapia FasLgene/cDNA, however these experiments were not successful. Aim #2 was to "Identify Regulatory Factors that Control NCC Responses to S. iniae." To accomplish this, a new membrane receptor has been identified that may control innate responses (including apoptosis) of NCC to S. iniae. The receptor is a membrane protein on teleost NCC. This protein (NCC cationic antimicrobial protein-1/ncamp-1/AAQ99138) has been sequenced and the cDNA cloned (A Y324398). In recombinant form, ncamp-l kills S. iniae in vitro. Specific aim 3 ("Characterize the Biological Properties of the S.iniae Capsular Polysaccharide") utilized an in- vitro model using rainbow trout primary skin epithelial cell mono layers. These experiments demonstrated colonization into epithelial cells followed by a rapid decline of viable intracellular bacteria and translocation out of the cell. This pathogenesis model suggested that the bacterium escapes the endosome and translocates through the rainbow trout skin barrier to further invade and infect the host. Specific aim #4 ("Development of an Acellular Vaccine") was not specifically addressed. These studies demonstrated that several different apoptotic regulatory genes/proteins are expressed by tilapia NCC. These are the first studies demonstrating that such factors exist in tilapia. Because tilapia NCC bind to and are activated by S. iniae bacterial DNA, we predict that the apoptotic regulatory activity of S. iniae previously demonstrated by our group may be associated with innate antibacterial responses in tilapia.
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Sessa, Guido, and Gregory B. Martin. molecular link from PAMP perception to a MAPK cascade associated with tomato disease resistance. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597918.bard.
The research problem: The detection of pathogen-associated molecular patterns (PAMPs) by plant pattern recognition receptors (PRRs) is a key mechanism by which plants activate an effective immune response against pathogen attack. MAPK cascades are important signaling components downstream of PRRs that transduce the PAMP signal to activate various defense responses. Preliminary experiments suggested that the receptor-like cytoplasmickinase (RLCK) Mai5 plays a positive role in pattern-triggered immunity (PTI) and interacts with the MAPKKK M3Kε. We thus hypothesized that Mai5, as other RLCKs, functions as a component PRR complexes and acts as a molecular link between PAMP perception and activation of MAPK cascades. Original goals: The central goal of this research was to investigate the molecular mechanisms by which Mai5 and M3Kε regulate plant immunity. Specific objectives were to: 1. Determine the spectrum of PAMPs whose perception is transmitted by M3Kε; 2. Identify plant proteins that act downstream of M3Kε to mediate PTI; 3. Investigate how and where Mai5 interacts with M3Kε in the plant cell; 4. Examine the mechanism by which Mai5 contributes to PTI. Changes in research directions: We did not find convincing evidence for the involvement of M3Kε in PTI signaling and substituted objectives 1 and 3 with research activities aimed at the analysis of transcriptomic profiles of tomato plants during the onset of plant immunity, isolation of the novel tomato PRR FLS3, and investigation of the involvement of the RLCKBSKs in PTI. Main achievements during this research program are in the following major areas: 1. Functional characterization of Mai5. The function of Mai5 in PTI signaling was demonstrated by testing the effect of silencing the Mai5 gene by virus-induced gene silencing (VIGS) experiments and in cell death assays. Domains of Mai5 that interact with MAPKKKs and subcellular localization of Mai5 were analyzed in detail. 2. Analysis of transcriptional profiles during the tomato immune responses to Pseudomonas syringae (Pombo et al., 2014). We identified tomato genes whose expression is induced specifically in PTI or in effector-triggered immunity (ETI). Thirty ETI-specific genes were examined by VIGS for their involvement in immunity and the MAPKKK EPK1, was found to be required for ETI. 3. Dissection of MAP kinase cascades downstream of M3Kε (Oh et al., 2013; Teper et al., 2015). We identified genes that encode positive (SGT and EDS1) and negative (WRKY1 and WRKY2) regulators of the ETI-associated cell death mediated by M3Kε. In addition, the MKK2 MAPKK, which acts downstream of M3Kε, was found to interact with the MPK3 MAPK and specific MPK3 amino acids involved interaction were identified and found to be required for induction of cell death. We also identified 5 type III effectors of the bacterial pathogen Xanthomonaseuvesicatoria that inhibited cell death induced by components of ETI-associated MAP kinase cascades. 4. Isolation of the tomato PRR FLS3 (Hind et al., submitted). FLS3, a novel PRR of the LRR-RLK family that specifically recognizes the flagellinepitope flgII-28 was isolated. FLS3 was shown to bind flgII-28, to require kinase activity for function, to act in concert with BAK1, and to enhance disease resistance to Pseudomonas syringae. 5. Functional analysis of RLCKs of the brassinosteroid signaling kinase (BSK) family.Arabidopsis and tomato BSKs were found to interact with PRRs. In addition, certain ArabidospsisBSK mutants were found to be impaired in PAMP-induced resistance to Pseudomonas syringae. Scientific and agricultural significance: Our research activities discovered and characterized new molecular components of signaling pathways mediating recognition of invading pathogens and activation of immune responses against them. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease.
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Sessa, Guido, and Gregory Martin. role of FLS3 and BSK830 in pattern-triggered immunity in tomato. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604270.bard.
Pattern-recognition receptors (PRRs) located on the plant cell surface initiate immune responses by perceiving conserved pathogen molecules known as pathogen-associated molecular patterns (PAMPs). PRRs typically function in multiprotein complexes that include transmembrane and cytoplasmickinases and contribute to the initiation and signaling of pattern-triggered immunity (PTI). An important challenge is to identify molecular components of PRR complexes and downstream signaling pathways, and to understand the molecular mechanisms that mediate their function. In research activities supported by BARD-4931, we studied the role of the FLAGELLIN SENSING 3 (FLS3) PRR in the response of tomato leaves to flagellin-derivedPAMPs and PTI. In addition, we investigated molecular properties of the tomato brassinosteroid signaling kinase 830 (BSK830) that physically interacts with FLS3 and is a candidate for acting in the FLS3 signaling pathway. Our investigation refers to the proposal original objectives that were to: 1) Investigate the role of FLS3 and its interacting proteins in PTI; 2) Investigate the role of BSK830 in PTI; 3) Examine molecular and phosphorylation dynamics of the FLS3-BSK830 interaction; 4) Examine the possible interaction of FLS3 and BSK830 with Pstand Xcveffectors. We used CRISPR/Cas9 techniques to develop plants carrying single or combined mutations in the FLS3 gene and in the paralogsFLS2.1 and FLS2.2 genes, which encode the receptor FLAGELLIN SENSING2 (FLS2), and analyzed their function in PTI. Domain swapping analysis of the FLS2 and FLS3 receptors revealed domains of the proteins responsible for PAMP detection and for the different ROS response initiated by flgII-28/FLS3 as compared to flg22/FLS2. In addition, in vitro kinase assays and point mutations analysis identified FLS2 and FLS3 domains required for kinase activity and ATP binding. In research activities on tomato BSK830, we found that it interacts with PRRs and with the co-receptor SERK3A and PAMP treatment affects part of these interactions. CRISPR/Cas9 bsk830 mutant plants displayed enhanced pathogen susceptibility and reduced ROS production upon PAMP treatment. In addition, BSK830 interacted with 8 Xanthomonastype III secreted effectors. Follow up analysis revealed that among these effectors XopAE is part of an operon, is translocated into plant cells, and displays E3 ubiquitinligase activity. Our investigation was also extended to other Arabidopsis and tomato BSK family members. Arabidopsis BSK5 localized to the plant cell periphery, interacted with receptor-like kinases, and it was phosphorylatedin vitro by the PEPR1 and EFRPRRs. bsk5 mutant plants displayed enhanced susceptibility to pathogens and were impaired in several, but not all, PAMP-induced responses. Conversely, BSK5 overexpression conferred enhanced disease resistance and caused stronger PTI responses. Genetic complementation suggested that proper localization, kinase activity, and phosphorylation by PRRs are critical for BSK5 function. BSK7 and BSK8 specifically interacted with the FLS2 PRR, their respective mutant plants were more susceptible to B. cinereaand displayed reduced flg22-induced responses. The tomato BSK Mai1 was found to interact with the M3KMAPKKK, which is involved in activation of cell death associated with effector-triggered immunity. Silencing of Mai1 in N. benthamianaplants compromised cell death induced by a specific class of immune receptors. In addition, co-expression of Mai1 and M3Kin leaves enhanced MAPKphosphorylation and cell death, suggesting that Mai1 acts as a molecular link between pathogen recognition and MAPK signaling. Finally, We identified the PP2C phosphatase Pic1 that acts as a negative regulator of PTI by interacting with and dephosphorylating the receptor-like cytoplasmickinase Pti1, which is a positive regulator of plant immunity. The results of this investigation shed new light on the molecular characteristics and interactions of components of the immune system of crop plants providing new knowledge and tools for development of novel strategies for disease control.
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Eldar, Avigdor, and Donald L. Evans. Streptococcus iniae Infections in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Toward the Pathogen and Vaccine Formulation. United States Department of Agriculture, December 2000. http://dx.doi.org/10.32747/2000.7575286.bard.
In Israel and in the U.S., Streptococcus iniae is responsible for considerable losses in various fish species. Poor understanding of its virulence factors and limited know-how-to of vaccine formulation and administration are the main reasons for the limited efficacy of vaccines. Our strategy was that in order to Improve control measures, both aspects should be equally addressed. Our proposal included the following objectives: (i) construction of host-pathogen interaction models; (ii) characterization of virulence factors and immunodominant antigens, with assessment of their relative importance in terms of protection and (iii) genetic identification of virulence factors and genes, with evaluation of the protective effect of recombinant proteins. We have shown that two different serotypes are involved. Their capsular polysaccharides (CPS) were characterized, and proved to play an important role in immune evasion and in other consequences of the infection. This is an innovative finding in fish bacteriology and resembles what, in other fields, has become apparent in the recent years: S. iniae alters surface antigens. By so doing, the pathogen escapes immune destruction. Immunological assays (agar-gel immunodiffusion and antibody titers) confirmed that only limited cross recognition between the two types occurs and that capsular polysaccharides are immunodominant. Vaccination with purified CPS (as an acellular vaccine) results in protection. In vitro and ex-vivo models have allowed us to unravel additional insights of the host-pathogen interactions. S. iniae 173 (type II) produced DNA fragmentation of TMB-8 cells characteristic of cellular necrosis; the same isolate also prevented the development of apoptosis in NCC. This was determined by finding reduced expression of phosphotidylserine (PS) on the outer membrane leaflet of NCC. NCC treated with this isolate had very high levels of cellular necrosis compared to all other isolates. This cellular pathology was confirmed by observing reduced DNA laddering in these same treated cells. Transmission EM also showed characteristic necrotic cellular changes in treated cells. To determine if the (in vitro) PCD/apoptosis protective effects of #173 correlated with any in vivo activity, tilapia were injected IV with #173 and #164 (an Israeli type I strain). Following injection, purified NCC were tested (in vitro) for cytotoxicity against HL-60 target cells. Four significant observations were made : (i) fish injected with #173 had 100-400% increased cytotoxicity compared to #164 (ii) in vivo activation occurred within 5 minutes of injection; (iii) activation occurred only within the peripheral blood compartment; and (iv) the isolate that protected NCC from apoptosis in vitro caused in vivo activation of cytotoxicity. The levels of in vivo cytotoxicity responses are associated with certain pathogens (pathogen associated molecular patterns/PAMP) and with the tissue of origin of NCC. NCC from different tissue (i.e. PBL, anterior kidney, spleen) exist in different states of differentiation. Random amplified polymorphic DNA (RAPD) analysis revealed the "adaptation" of the bacterium to the vaccinated environment, suggesting a "Darwinian-like" evolution of any bacterium. Due to the selective pressure which has occurred in the vaccinated environment, type II strains, able to evade the protective response elicited by the vaccine, have evolved from type I strains. The increased virulence through the appropriation of a novel antigenic composition conforms with pathogenic mechanisms described for other streptococci. Vaccine efficacy was improved: water-in-oil formulations were found effective in inducing protection that lasted for a period of (at least) 6 months. Protection was evaluated by functional tests - the protective effect, and immunological parameters - elicitation of T- and B-cells proliferation. Vaccinated fish were found to be resistant to the disease for (at least) six months; protection was accompanied by activation of the cellular and the humoral branches.
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Elbaum, Michael, and Peter J. Christie. Type IV Secretion System of Agrobacterium tumefaciens: Components and Structures. United States Department of Agriculture, March 2013. http://dx.doi.org/10.32747/2013.7699848.bard.
Objectives: The overall goal of the project was to build an ultrastructural model of the Agrobacterium tumefaciens type IV secretion system (T4SS) based on electron microscopy, genetics, and immunolocalization of its components. There were four original aims: Aim 1: Define the contributions of contact-dependent and -independent plant signals to formation of novel morphological changes at the A. tumefaciens polar membrane. Aim 2: Genetic basis for morphological changes at the A. tumefaciens polar membrane. Aim 3: Immuno-localization of VirB proteins Aim 4: Structural definition of the substrate translocation route. There were no major revisions to the aims, and the work focused on the above questions. Background: Agrobacterium presents a unique example of inter-kingdom gene transfer. The process involves cell to cell transfer of both protein and DNA substrates via a contact-dependent mechanism akin to bacterial conjugation. Transfer is mediated by a T4SS. Intensive study of the Agrobacterium T4SS has made it an archetypal model for the genetics and biochemistry. The channel is assembled from eleven protein components encoded on the B operon in the virulence region of the tumor-inducing plasmid, plus an additional coupling protein, VirD4. During the course of our project two structural studies were published presenting X-ray crystallography and three-dimensional reconstruction from electron microscopy of a core complex of the channel assembled in vitro from homologous proteins of E. coli, representing VirB7, VirB9, and VirB10. Another study was published claiming that the secretion channels in Agrobacterium appear on helical arrays around the membrane perimeter and along the entire length of the bacterium. Helical arrangements in bacterial membranes have since fallen from favor however, and that finding was partially retracted in a second publication. Overall, the localization of the T4SS within the bacterial membranes remains enigmatic in the literature, and we believe that our results from this project make a significant advance. Summary of achievements : We found that polar inflations and other membrane disturbances relate to the activation conditions rather than to virulence protein expression. Activation requires low pH and nutrient-poor medium. These stress conditions are also reflected in DNA condensation to varying degrees. Nonetheless, they must be considered in modeling the T4SS as they represent the relevant conditions for its expression and activity. We identified the T4SS core component VirB7 at native expression levels using state of the art super-resolution light microscopy. This marker of the secretion system was found almost exclusively at the cell poles, and typically one pole. Immuno-electron microscopy identified the protein at the inner membrane, rather than at bridges across the inner and outer membranes. This suggests a rare or transient assembly of the secretion-competent channel, or alternatively a two-step secretion involving an intermediate step in the periplasmic space. We followed the expression of the major secreted effector, VirE2. This is a single-stranded DNA binding protein that forms a capsid around the transferred oligonucleotide, adapting the bacterial conjugation to the eukaryotic host. We found that over-expressed VirE2 forms filamentous complexes in the bacterial cytoplasm that could be observed both by conventional fluorescence microscopy and by correlative electron cryo-tomography. Using a non-retentive mutant we observed secretion of VirE2 from bacterial poles. We labeled the secreted substrates in vivo in order detect their secretion and appearance in the plant cells. However the low transfer efficiency and significant background signal have so far hampered this approach.
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Schwartz, Bertha, Vaclav Vetvicka, Ofer Danai, and Yitzhak Hadar. Increasing the value of mushrooms as functional foods: induction of alpha and beta glucan content via novel cultivation methods. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600033.bard.
During the granting period, we performed the following projects: Firstly, we differentially measured glucan content in several pleurotus mushroom strains. Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. In our first study, we explored several Pleurotus species for their total, β and α-glucan content. Pleurotuseryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotuseryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate. We then compared the immune-modulating activity of glucans extracted from P. ostreatus and P. eryngii on phagocytosis of peripheral blood neutrophils, and superoxide release from HL-60 cells. The results suggest that the anti-inflammatory properties of these glucans are partially mediated through modulation of neutrophileffector functions (P. eryngiiwas more effective). Additionally, both glucans dose-dependently competed for the anti-Dectin-1 and anti-CR3 antibody binding. We then tested the putative anti-inflammatory effects of the extracted glucans in inflammatory bowel disease (IBD) using the dextran sulfate sodium (DSS)–induced model in mice. The clinical symptoms of IBD were efficiently relieved by the treatment with two different doses of the glucan from both fungi. Glucan fractions, from either P. ostreatus or P. eryngii, markedly prevented TNF-α mediated inflammation in the DSS–induced inflamed intestine. These results suggest that there are variations in glucan preparations from different fungi in their anti-inflammatory ability. In our next study, we tested the effect of glucans on lipopolysaccharide (LPS)-induced production of TNF-α. We demonstrated that glucan extracts are more effective than mill mushroom preparations. Additionally, the effectiveness of stalk-derived glucans were slightly more pronounced than of caps. Cap and stalk glucans from mill or isolated glucan competed dose-dependently with anti-Dectin-and anti-CR-3 antibodies, indicating that they contain β-glucans recognized by these receptors. Using the dextran sulfate sodium (DSS)-inflammatory bowel disease mice model, intestinal inflammatory response to the mill preparations was measured and compared to extracted glucan fractions from caps and stalks. We found that mill and glucan extracts were very effective in downregulatingIFN-γ and MIP-2 levels and that stalk-derived preparations were more effective than from caps. The tested glucans were equally effective in regulating the number of CD14/CD16 monocytes and upregulating the levels of fecal-released IgA to almost normal levels. In conclusion, the most effective glucans in ameliorating some IBD-inflammatory associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii. These spatial distinctions may be helpful in selecting more effective specific anti-inflammatory mushrooms-derived glucans. We additionally tested the effect of glucans on lipopolysaccharide-induced production of TNF-α, which demonstrated stalk-derived glucans were more effective than of caps-derived glucans. Isolated glucans competed with anti-Dectin-1 and anti-CR3 antibodies, indicating that they contain β-glucans recognized by these receptors. In conclusion, the most effective glucans in ameliorating IBD-associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii grown at higher concentrations of OMSW. We conclude that these stress-induced growing conditions may be helpful in selecting more effective glucans derived from edible mushrooms. Based on the findings that we could enhance glucan content in Pleurotuseryngii following cultivation of the mushrooms on a substrate containing different concentrations of olive mill solid waste (OMSW) and that these changes are directly related to the content of OMSW in the growing substrate we tested the extracted glucans in several models. Using dextran sulfate sodium (DSS)–inflammatory bowel disease (IBD) mice model, we measured the colonic inflammatory response to the different glucan preparations. We found that the histology damaging score (HDS) resulting from DSS treatment reach a value of 11.8 ± 2.3 were efficiently downregulated by treatment with the fungal extracted glucans, glucans extracted from stalks cultivated at 20% OMSWdownregulated to a HDS value of 6.4 ± 0.5 and at 80% OMSW showed the strongest effects (5.5 ± 0.6). Similar downregulatory effects were obtained for expression of various intestinal cytokines. All tested glucans were equally effective in regulating the number of CD14/CD16 monocytes from 18.2 ± 2.7 % for DSS to 6.4 ± 2.0 for DSS +glucans extracted from stalks cultivated at 50% OMSW. We finally tested glucans extracted from Pleurotuseryngii grown on a substrate containing increasing concentrations of olive mill solid waste (OMSW) contain greater glucan concentrations as a function of OMSW content. Treatment of rat Intestinal epithelial cells (IEC-6) transiently transfected with Nf-κB fused to luciferase demonstrated that glucans extracted from P. eryngii stalks grown on 80% OMSWdownregulatedTNF-α activation. Glucans from mushrooms grown on 80% OMSW exerted the most significant reducing activity of nitric oxide production in lipopolysaccharide (LPS) treated J774A.1 murine macrophages. The isolated glucans were tested in vivo using the Dextran Sodium Sulfate (DSS) induced colitis in C57Bl/6 mice and found to reduce the histology damaging score resulting from DSS treatment. Expression of various intestinal cytokines were efficiently downregulated by treatment with the fungal extracted glucans. We conclude that the stress-induced growing conditions exerted by OMSW induces production of more effective anti-inflammatory glucans in P. eryngii stalks.
