Journal articles: 'Antigen specificity'

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Rhodes, S. G., D. Gavier-Widen, B. M. Buddle, A. O. Whelan, M. Singh, R. G. Hewinson, and H. M. Vordermeier. "Antigen Specificity in Experimental Bovine Tuberculosis." Infection and Immunity 68, no. 5 (May 1, 2000): 2573–78. http://dx.doi.org/10.1128/iai.68.5.2573-2578.2000.

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ABSTRACT This report describes the kinetics of T-cell responses to a panel of mycobacterial antigens (PPD-M, PPD-A, ESAT-6, Ag85, 38kD, MPB64, MPB70, MPB83, hsp16.1, hsp65, and hsp70) following experimental infection of cattle with Mycobacterium bovis. Increased antigen-specific lymphocyte proliferation, gamma interferon, and interleukin-2 responses were observed in all calves following infection. Positive lymphocyte proliferation and cytokine responses to PPD-M and ESAT-6 were observed throughout the infection period studied. In contrast, responses to all other antigens were more variable and were not constantly present, suggesting that antigen cocktails rather than individual antigens should be used for immunodiagnosis. The detection of cytokine responses in the absence of lymphocyte proliferation, particularly during the early stages of infection, suggests a role for antigen-specific cytokine readout systems in the early identification of M. bovis infection in cattle.

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Jain, Deepti, and Dinakar M. Salunke. "Antibody specificity and promiscuity." Biochemical Journal 476, no. 3 (February 5, 2019): 433–47. http://dx.doi.org/10.1042/bcj20180670.

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Abstract The immune system is capable of making antibodies against anything that is foreign, yet it does not react against components of self. In that sense, a fundamental requirement of the body's immune defense is specificity. Remarkably, this ability to specifically attack foreign antigens is directed even against antigens that have not been encountered a priori by the immune system. The specificity of an antibody for the foreign antigen evolves through an iterative process of somatic mutations followed by selection. There is, however, accumulating evidence that the antibodies are often functionally promiscuous or multi-specific which can lead to their binding to more than one antigen. An important cause of antibody cross-reactivity is molecular mimicry. Molecular mimicry has been implicated in the generation of autoimmune response. When foreign antigen shares similarity with the component of self, the antibodies generated could result in an autoimmune response. The focus of this review is to capture the contrast between specificity and promiscuity and the structural mechanisms employed by the antibodies to accomplish promiscuity, at the molecular level. The conundrum between the specificity of the immune system for foreign antigens on the one hand and the multi-reactivity of the antibody on the other has been addressed. Antibody specificity in the context of the rapid evolution of the antigenic determinants and molecular mimicry displayed by antigens are also discussed.

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Kendall-Taylor, P., D. Jones, and S. Atkinson. "The specificity of autoantibodies in Graves' ophthalmopathy." Acta Endocrinologica 116, no. 1_Suppl (August 1987): S330—S333. http://dx.doi.org/10.1530/acta.0.114s330.

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Abstract. An autoantibody to orbital antigens is found in patients with Graves' ophthalmopathy. This autoantibody also binds to skeletal muscle antigen. Occasional positive responses have been seen in patients with Hashimoto's disease and with non-organ-specific autoimmune disease. Eye muscle has a higher innervation ratio than skeletal muscle and may be of different embryological origin, but it is nevertheless closely related to skeletal muscle and it is perhaps not surprising that the antibody should interact with both these types of muscle. What remains quite unexplained, is why the disease process apparently affects eye muscle only. The antigen appears to be distinct from thyroidal antigens, but further work with a larger patient population is necessary before one can be certain of this. To date it has been possible to exclude the cytoskeletal proteins, myosin and actin, and also the TSH receptor as possible candidates for the responsible antigens. Further studies are in progress to elucidate the nature of this muscle antigen.

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Jiang, Ning, Ke-yue Ma, Alexandra A. Schonnesen, Chenfeng He, Amanda Xia, Eric Sun, Eunise Chen, Katherine Sebastian, Robert Balderas, and Mrinalini Kulkarni-Date. "High-Throughput and High-Dimensional Single Cell Analysis of Antigen-Specific CD8+ T cells." Journal of Immunology 206, no. 1_Supplement (May 1, 2021): 27.22. http://dx.doi.org/10.4049/jimmunol.206.supp.27.22.

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Abstract Although critical to T cell function, antigen specificity is often omitted in high-throughput multi-omics based T cell profiling due to technical challenges. We describe a high-dimensional, tetramer-associated T cell receptor sequencing (TetTCR-SeqHD) method to simultaneously profile TCR sequences, cognate antigen specificities, targeted gene-expression, and surface-protein expression from tens of thousands of single cells. Using polyclonal CD8+ T cells with known antigen specificity and TCR sequences, we demonstrated over 98% precision for detecting the correct antigen specificity. We also evaluated gene-expression and phenotypic differences among antigen-specific CD8+ T cells and characterized phenotype signatures of influenza- and EBV-specific CD8+ T cells that are unique to their pathogen targets. Moreover, with the high-throughput capacity of profiling hundreds of antigens simultaneously, we applied TetTCR-SeqHD to identify antigens that preferentially enrich cognate CD8+ T cells in type 1 diabetes patients compared to healthy controls, and discovered a TCR that cross reacts between diabetic and microbiome antigens. TetTCR-SeqHD is a powerful approach for profiling T cell responses.

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Lesavre, Philippe. "Antineutrophil Cytoplasmic Autoantibodies Antigen Specificity." American Journal of Kidney Diseases 18, no. 2 (August 1991): 159–63. http://dx.doi.org/10.1016/s0272-6386(12)80873-0.

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Bolhuis, Reinder L. H., Els Sturm, Jan Willem Gratama, and Eric Braakman. "Engineering T lymphocyte antigen specificity." Journal of Cellular Biochemistry 47, no. 4 (December 1991): 306–10. http://dx.doi.org/10.1002/jcb.240470404.

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Klinger, Mark, Ruth Taniguchi, Joyce Hu, Tim Hayes, Tobias Wittkop, Thomas Asbury, Martin Moorhead, et al. "A scalable multiplex assay enabling assessment of T cell receptor specificity to hundreds of self- and pathogen-derived antigens." Journal of Immunology 196, no. 1_Supplement (May 1, 2016): 209.4. http://dx.doi.org/10.4049/jimmunol.196.supp.209.4.

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Abstract Monitoring antigen-specific T cells is critical for the study of immune responses and development of biomarkers and immunotherapeutics. We previously developed and validated a novel multiplex assay (MIRA, or Multiplexed Identification of T cell Receptor Antigen specificity) that combines conventional immune monitoring techniques and TCR repertoire sequencing to assess T cell specificity to large numbers of query antigens. MIRA is a sensitive assay enabling detection of antigen-specific TCR clonotypes well below the limit of detection of conventional immune monitoring assays including flow cytometry and ELISPOT. Here we report the results from a scaled-up version of the assay using 270 different query peptide antigens (159 self- and 111 pathogen-derived). We identified >500 TCR clonotypes at frequencies as low as 1 per million T cells that were specific to 41 query antigens from 6 healthy HLA-A*02-positive individuals. Most of the antigen-specific TCRs identified recognized one of 27 different peptides derived from a variety of pathogens including CMV, EBV, Flu, Rotavirus, HSV, mTB, WNV and HIV. A subset of antigen-specific TCRs recognized one of 14 different peptides derived from self including MART1, RCC, BCL-2, MAGE, STEAP1, KLK4, CAMEL and MOG. These data support the notion that escape and survival of self antigen-specific T cells occurs without causing overt autoimmunity in healthy individuals. We show here that MIRA can be used to assess TCR specificities to hundreds of query antigens simultaneously. The assay is highly scalable and can be easily modified to accommodate thousands of additional query antigens. This technology may be used to monitor T cell specificity to antigens relevant to infection, autoimmunity and cancer.

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Shahi, Payam, Bruce Adams, Daniel Reyes, Shamoni Maheshwari, Nima Mousavi, Sreenath Krishnan, Nandhini Ramen, et al. "High-Throughput Antibody Discovery Using Barcode Enabled Antigen Mapping (BEAM." Journal of Immunology 210, no. 1_Supplement (May 1, 2023): 249.28. http://dx.doi.org/10.4049/jimmunol.210.supp.249.28.

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Abstract Multi-analyte single cell technologies have potential to greatly accelerate antibody discovery by identifying antigen-specific B cells. Barcode Enabled Antigen Mapping (BEAM) provides a high-throughput, multimodal analysis of antigen-bound B cells (BEAM-Ab) using 10x Genomics Chromium Single Cell Immune Profiling v2 Solution and novel computational approaches to discover B-cell receptor (BCR) sequences for further functional characterization. To demonstrate the antigen sensitivity of BEAM-Ab, we spiked in 5% Hen Egg Lysozyme (HEL) and 5% gp120 transgenic B cells in 90% wild type non-transgenic splenocytes. The cells were screened using a panel of barcoded antigens and then CD19+PE+ (antigen+) B cells were isolated using flow cytometry. Single cell gene expression, BCR, and antigen barcode analysis indicated clonotype specificity to the respective antigens in the sorted cells. Furthermore, we demonstrated BEAM-Ab specificity by analyzing a convalescent COVID patient sample against an antigen panel containing five different COVID antigens and a negative control. Analysis of this COVID sample suggests the clonal expansion of B cells recognizing the ectodomain of the wild type SARS-CoV2 spike protein, receptor binding domain of spike protein, and the ectodomain of the D614G mutant spike protein. We did not observe any clonal expansion to Omicron-specific antigen or the non-specific negative control in our dataset. Our data demonstrates that BEAM-Ab is an effective antibody discovery tool. BEAM-Ab unlocks the ability to rapidly screen large numbers of samples with an accurate single cell resolution and antigen specificity, with the entire workflow generating the candidate sequences just one week after sample processing.

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Tseng, Diane, Shin-Heng Chiou, Xinbo Yang, Alexandre Reuben, Julie Wilhelmy, Alana McSween, Stephanie Conley, et al. "Discovery of a novel shared tumor antigen in human lung cancer." Journal of Clinical Oncology 38, no. 15_suppl (May 20, 2020): 3087. http://dx.doi.org/10.1200/jco.2020.38.15_suppl.3087.

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3087 Background: While there has been much attention on mutation-associated neoantigens in tumors, there is less known about non-mutated tumor antigens that are shared across individuals. Understanding tumor-infiltrating T cell recognition of shared tumor antigens is important for understanding cancer immune recognition and escape, and may reveal novel targets for therapy. Methods: We have established a novel approach for discovering shared tumor antigens in human lung cancer. This approach involves identifying candidate T cell receptor (TCR) alpha/beta pairs that are predicted to exhibit specificity for shared tumor antigens in the context of a given human leukocyte antigen (HLA). We then screen the T cell receptor for binding to yeast display libraries of peptide-HLA. The Mark Davis lab at Stanford has previously developed an algorithm that groups T cell receptors into antigen specificity groups based on shared motifs within the TCR complementarity-determining region 3 (CDR3) sequences. Leveraging a dataset of over 700K CDR3 sequences from 178 HLA-typed non-small cell lung cancer (NSCLC) patients, we have found up to 4,300 antigen specificity groups after applying stringent cutoffs. We sequenced TCR alpha/beta pairs from 15 patients with lung adenocarcinoma (n = 4,705). Results: We identified an antigen specificity group enriched in tumor compared to adjacent uninvolved lungs. Antigen screening of the T cell receptor belonging to this specificity group using an A02 yeast display libraries led to the identification of a dominant peptide after four rounds of enrichment. We functionally validated that the peptide derived from the protein TMEM161A stimulated Jurkat cells expressing the TCR alpha/beta receptor of interest. We show that full-length TMEM161A protein is processed and presented into a peptide that stimulates primary T cells expressing the TCR alpha/beta receptor. We observe that a peptide from Epstein-Barr virus (EBV) protein LMP2 also stimulated the same TCR alpha/beta receptor. We have show that TMEM161A RNA and protein are overexpressed in human lung cancer compared to adjacent uninvolved lungs. Conclusions: We have demonstrated a novel approach toward antigen discovery and identified a shared tumor antigen TMEM161A in human lung cancer.

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Zollinger, Wendell D., Elizabeth E. Moran, and Deborah H. Schmiel. "Characterization of an Antibody Depletion Assay for Analysis of Bactericidal Antibody Specificity." Clinical and Vaccine Immunology 16, no. 12 (October 14, 2009): 1789–95. http://dx.doi.org/10.1128/cvi.00255-09.

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ABSTRACT Serum bactericidal antibodies are important for protection against systemic Neisseria meningitidis infections. Consequently, identifying the specific targets of bactericidal antibodies is important for understanding protective immunity to meningococcal disease and for vaccine development and evaluation. We have developed a new assay that can be used to investigate the specificity of serum bactericidal antibodies. Prior to testing for bactericidal activity, antibodies specific for a given antigen or group of antigens are depleted from a serum sample by incubation with the antigen(s) bound to the wells of a 96-well microplate. A dilution series of the antigen is bound to the plate to assess the effectiveness of the antigen in removing the bactericidal antibodies. Removal of antibodies with solid-phase antigen prior to bactericidal testing avoids depletion of complement by soluble immune complexes that can form when soluble antigen is present in the bactericidal test mixture (direct inhibition). The parameters associated with this assay are investigated and compared with those associated with a direct-inhibition assay. The bactericidal depletion assay can be an effective tool for studying the specificity of serum bactericidal antibodies.

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Pantophlet, Ralph, Lore Brade, Lenie Dijkshoorn, and Helmut Brade. "Specificity of Rabbit Antisera against Lipopolysaccharide of Acinetobacter." Journal of Clinical Microbiology 36, no. 5 (1998): 1245–50. http://dx.doi.org/10.1128/jcm.36.5.1245-1250.1998.

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Acinetobacter has been reported to be involved in hospital-acquired infections with increasing frequency. However, clinical laboratories still lack simple methods that allow the accurate identification of Acinetobacter strains at the species level. For this study, proteinase K-digested whole-cell lysates from 44 clinical and environmental isolates were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with hyperimmune rabbit sera to examine the possibility of developing a serotyping scheme based on the O antigen of Acinetobacterlipopolysaccharide (LPS). The antisera, obtained by immunization of rabbits with 13 of the heat-killed isolates investigated, were characterized by Western blotting and enzyme immunoassay by using proteinase K-digested whole-cell lysates and phenol-water-extracted LPS as antigens. In both assays, the antisera were shown to be highly specific for the homologous antigen. In addition, assignment ofAcinetobacter LPS to the smooth or the rough phenotype was shown not to be reliable when it was based only on the results obtained with silver-stained gels. O-antigen reactivity, determined by Western blot analysis, was observed with 11 of the 31 isolates, most of which belonged to the species Acinetobacter baumannii (DNA group 2) and the unnamed DNA group 3. Interestingly, some O antigens were found in a DNA group different from that of the strain used for immunization. The results indicate that O serotyping ofAcinetobacter strains is feasible and thus may provide a simple method for the routine identification of these opportunistic pathogens.

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Maier, Cheryl L., Amanda Mener, Seema R. Patel, Ryan P. Jajosky, Ashley L. Bennett, Connie M. Arthur, Jeanne E. Hendrickson, and Sean R. Stowell. "Antibody-mediated immune suppression by antigen modulation is antigen-specific." Blood Advances 2, no. 21 (November 9, 2018): 2986–3000. http://dx.doi.org/10.1182/bloodadvances.2018018408.

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Abstract Alloantibodies developing after exposure to red blood cell (RBC) alloantigens can complicate pregnancy and transfusion therapy. The only method currently available to actively inhibit RBC alloantibody formation is administration of antigen-specific antibodies, a phenomenon termed antibody-mediated immune suppression (AMIS). A well-known example of AMIS is RhD immune globulin prophylaxis to prevent anti-D formation in RhD− individuals. However, whether AMIS is specific or impacts alloimmunization to other antigens on the same RBC remains unclear. To evaluate the specificity of AMIS, we passively immunized antigen-negative recipients with anti-KEL or anti-hen egg lysozyme (HEL) antibodies, followed by transfusion of murine RBC expressing both the HEL-ovalbumin-Duffy (HOD) and human KEL antigens (HOD × KEL RBC). Significant immunoglobulin G deposition on transfused HOD × KEL RBC occurred in all passively immunized recipients. Complement deposition and antigen modulation of the KEL antigen occurred on transfused RBC only in anti-KEL–treated recipients, whereas HEL antigen levels decreased only in the presence of anti-HEL antibodies. Western blot analysis confirmed the specificity of antigen loss, which was not attributable to RBC endocytosis and appears distinct for the 2 antigens. Specifically, removal of KEL was attenuated by clodronate treatment, whereas loss of HEL was unaffected by clodronate in vivo but sensitive to protease treatment in vitro. Antigen-specific modulation correlated with antigen-specific AMIS, with anti-KEL treated recipients forming antibodies to the HOD antigen and anti-HEL–treated recipients developing antibodies to the KEL antigen. Together, these results demonstrate that passively administered antibodies can selectively inhibit the immune response to a specific antigen.

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Domínguez, J. A., N. Galí, P. Pedroso, A. Fargas, E. Padilla, J. M. Manterola, and L. Matas. "Comparison of the Binax Legionella Urinary Antigen Enzyme Immunoassay (EIA) with the Biotest Legionella Urin Antigen EIA for Detection of Legionella Antigen in both Concentrated and Nonconcentrated Urine Samples." Journal of Clinical Microbiology 36, no. 9 (1998): 2718–22. http://dx.doi.org/10.1128/jcm.36.9.2718-2722.1998.

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We evaluated a newly commercial enzyme immunoassay (EIA) (BiotestLegionella Urin Antigen EIA; Biotest AG, Dreieich, Germany) for detection of antigens of all Legionella pneumophilaserogroups with a relatively wide spectrum of cross-reactivity as well as antigens of other Legionella spp. by comparing its sensitivity and specificity with those of an EIA for detection ofL. pneumophila serogroup 1 antigen (Legionella urinary antigen EIA; Binax, Portland, Maine). Both tests were performed with both concentrated and nonconcentrated urine samples. We also evaluated the capabilities of both EIAs to detect extracted soluble antigens of American Type Culture Collection (ATCC) Legionella strains (L. pneumophila serogroups 1 to 14, L. bozemanii, and L. longbeachae). The sensitivity of the Biotest EIA was 66.66% in nonconcentrated urine and 86.66% in concentrated urine. The sensitivity of the Binax EIA was 63.76% and 88.88% in nonconcentrated and concentrated urine, respectively. The specificity was 100% in nonconcentrated and concentrated urine for both assays. The Binax EIA and Biotest EIA detected extracted soluble antigens of L. pneumophila serogroups 1 to 14 and L. bozemanii ATCC strains. The cross-reactions observed with the Binax EIA were probably due to common epitopes directly related to lipopolysaccharide. Further studies are required to determine the usefulness of the Binax EIA for detection of urinary antigens fromLegionella species and serogroups other than L. pneumophila serogroup 1. The Biotest EIA proved to be as rapid, sensitive, and specific as the Binax EIA for the diagnosis of legionellosis. Concentration of antigen present in urine increased the sensitivities of both techniques with no reduction in specificity.

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Kumar, D., and S. N. S. Gaur. "Comparative evaluation of various immunodiagnostic tests for the diagnosis ofTaenia soliumcysticercosis in pigs, using fractionated antigens." Journal of Helminthology 63, no. 1 (March 1989): 13–17. http://dx.doi.org/10.1017/s0022149x00008658.

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ABSTRACTThe sensitivity and specificity of double immunodiffusion (DID), indirect haemagglutination test (IHA), immunoelectrophoresis (IEP), counterimmunoelectrophoresis (CIEP) and enzyme-linked immunosorbent assay (ELISA) were evaluated and compared using saline extracted ofTaenia soliumlarval scolex and its Sephadex G-200 fractionated 1st and 2nd peak as antigens. Various immunodiagnostic tests gave different results with different antigens. Highest sensitivity (92·5%) was obtained with ELISA using 1st peak antigen and lowest sensitivity was obtained with DID. However, 88·4% and 84·6% sensitivity was obtained with IHA and CIEP respectively using scolex antigen. CIEP gave better results as compared to IEP. Crude antigen gave high sensitivity but less specificity. It was concluded that CIEP can be used as a field test for the anti-mortem diagnosis and ELISA can be employed for laboratory confirmation ofT. soliumcysticercosis in pigs using frationated 1st peak antigen.

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Otsuyama, Ken-ichiro, Hidehiro Tsuneoka, Kaori Kondou, Masashi Yanagihara, Nobuko Tokuda, Bungo Shirasawa, and Kiyoshi Ichihara. "Development of a Highly Specific IgM Enzyme-Linked Immunosorbent Assay for Bartonella henselae Using RefinedN-Lauroyl-Sarcosine-Insoluble Proteins for Serodiagnosis of Cat Scratch Disease." Journal of Clinical Microbiology 54, no. 4 (February 10, 2016): 1058–64. http://dx.doi.org/10.1128/jcm.03009-15.

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The conventional anti-Bartonella henselaeIgM enzyme-linked immunosorbent assay (IgM-ELISA) methods for diagnosing cat scratch disease (CSD) remain poor in both sensitivity and specificity. We sought to develop an IgM-ELISA with improved accuracy in the serodiagnosis of CSD by exploring the antigens that are most suitable for an ELISA. We prepared 5 different protein antigens: antigen I (sonicatedB. henselaewhole-cell antigen), antigen II (N-lauroyl-sarcosine-insoluble antigen), antigen III (processed sarcosine-soluble antigen), and antigen IV and antigen V (sarcosine-insoluble and sarcosine-soluble antigens refined by DEAE-Sepharose Fast Flow ion-exchange chromatography). The IgM antibodies in the sera of 47 patients with clinically suspected CSD (24 definite, 23 suspected) and of 85 healthy individuals were examined by ELISAs using the 5 antigens, and the results were compared with those of an IgM indirect fluorescent antibody assay (IgM-IFA). In a reference panel, which consisted of 5 positive and 5 negative sera, antigen I and antigen III failed to distinguish between the two statuses, whereas the other three antigens succeeded in distinguishing between them. When the cutoff value was set at the 98th percentile of the ELISA index for healthy individuals, the sensitivity of IgM-IFA for the 24 cases of definite CSD was 54%, whereas the sensitivities of the IgM-ELISAs with antigen II, IV, and V were 75%, 83%, and 75%, respectively. The sensitivities of these three IgM-ELISAs for all 47 of the clinically suspected cases were 49%, 64%, and 51%, respectively. In contrast, the sensitivity of IgM-IFA was 28%. These results indicate that the refined sarcosine-insoluble proteins (antigen IV), which possessed the highest specificity among the 5 antigens, are the most appropriate for developing an IgM-ELISA for the highly specific serodiagnosis of CSD.

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Moon, James J., and Marc K. Jenkins. "Characterization of naive CD4+ T cells with specificity to self-antigen (137.21)." Journal of Immunology 182, no. 1_Supplement (April 1, 2009): 137.21. http://dx.doi.org/10.4049/jimmunol.182.supp.137.21.

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Abstract During thymic development, T cells with specificity to self-antigens are deleted, thereby ensuring that the peripheral repertoire is devoid of potentially autoreactive clones. However, the ultra-low frequency of naive epitope-specific T cells has made the direct test of this theory technically unfeasible in the past. Using peptide:MHC (pMHC) multimers coupled with magnetic bead enrichment, we have directly studied endogenous polyclonal populations of naive CD4+ T cells with specificity for an I-Ab-restricted model antigen, 2W1S, that is foreign in C57BL/6 mice (B6) or self in mice transgenically expressing the model antigen (Act-2W). Act-2W mice contained a population of 2W1S-specific T cells that was about 25% the size of that in B6 mice, demonstrating that thymic deletion of self-antigen specific T cells is incomplete. Nonetheless, these cells were tolerant to 2W1S, as they did not develop autoimmune responses or respond to large doses of exogenous 2W1S antigen administered in vivo. Antigen receptors expressed by these cells exhibited features of reduced pMHC ligand binding affinity, indicating a preferential loss of high-affinity 2W1S-specific clones during thymic selection. Moreover, a greater proportion of 2W1S-specific T cells expressed FoxP3 in Act-2W mice than in B6 counterparts, suggesting that regulatory T cell development may also function as a mechanism of T cell tolerance to self-antigens. This work was funded by NIH grants PO1-AI35296 and F32-AI063793.

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Williams, Ifor. "Liver NK cells with antigen specificity." Science 370, no. 6515 (October 22, 2020): 418.12–420. http://dx.doi.org/10.1126/science.370.6515.418-l.

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Born, Willi K., Rebecca L. O'Brien, and Robert L. Modlin. "Antigen specificity of γδ T lymphocytes." FASEB Journal 5, no. 12 (September 1991): 2699–705. http://dx.doi.org/10.1096/fasebj.5.12.1717333.

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dos Santos, J. I. "Specificity of HIV antigen capture assays." AIDS 3, no. 8 (August 1989): 545. http://dx.doi.org/10.1097/00002030-198908000-00012.

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Politz, Samuel M., Karl J. Chin, and Daniel L. Herman. "Genetic Analysis of Adult-Specific Surface Antigenic Differences Between Varieties of the Nematode Caenorhabditis elegans." Genetics 117, no. 3 (November 1, 1987): 467–76. http://dx.doi.org/10.1093/genetics/117.3.467.

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ABSTRACT We have studied developmental stage-specificity and genetic specification of surface antigens in the nematode Caenorhabditis elegans. Rabbit antisera directed against the adult C. elegans cuticle were used in conjunction with antiserum adsorption experiments to obtain antibody reagents with specificity for the adult surface. Adult-specific antibodies were used to identify several varietal strains of C. elegans that display antigen-negative phenotypes as adults. Genetic mapping results using the surface antigen phenotype as a marker indicated that a single gene (designated srf-1) or cluster of genes on linkage group II determines the adult surface antigen phenotype.

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Dorman, A. M., D. Chin, and M. Leader. "Specificity of colon specific antigen and colon ovarian tumour antigen." Journal of Clinical Pathology 45, no. 10 (October 1, 1992): 932–33. http://dx.doi.org/10.1136/jcp.45.10.932.

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Shevyrev, D. V., V. P. Tereshchenko, and S. V. Sennikov. "The Enigmatic Nature of the TCR-pMHC Interaction: Implications for CAR-T and TCR-T Engineering." International Journal of Molecular Sciences 23, no. 23 (November 25, 2022): 14728. http://dx.doi.org/10.3390/ijms232314728.

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The interaction of the T-cell receptor (TCR) with a peptide in the major histocompatibility complex (pMHC) plays a central role in the adaptive immunity of higher chordates. Due to the high specificity and sensitivity of this process, the immune system quickly recognizes and efficiently responds to the appearance of foreign and altered self-antigens. This is important for ensuring anti-infectious and antitumor immunity, in addition to maintaining self-tolerance. The most common parameter used for assessing the specificity of TCR-pMHC interaction is affinity. This thermodynamic characteristic is widely used not only in various theoretical aspects, but also in practice, for example, in the engineering of various T-cell products with a chimeric (CAR-T) or artificial (TCR-engineered T-cell) antigen receptor. However, increasing data reveal the fact that, in addition to the thermodynamic component, the specificity of antigen recognition is based on the kinetics and mechanics of the process, having even greater influence on the selectivity of the process and T lymphocyte activation than affinity. Therefore, the kinetic and mechanical aspects of antigen recognition should be taken into account when designing artificial antigen receptors, especially those that recognize antigens in the MHC complex. This review describes the current understanding of the nature of the TCR-pMHC interaction, in addition to the thermodynamic, kinetic, and mechanical principles underlying the specificity and high sensitivity of this interaction.

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Choe, Joseph H., Payal B. Watchmaker, Milos S. Simic, Ryan D. Gilbert, Aileen W. Li, Nira A. Krasnow, Kira M. Downey, et al. "SynNotch-CAR T cells overcome challenges of specificity, heterogeneity, and persistence in treating glioblastoma." Science Translational Medicine 13, no. 591 (April 28, 2021): eabe7378. http://dx.doi.org/10.1126/scitranslmed.abe7378.

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Treatment of solid cancers with chimeric antigen receptor (CAR) T cells is plagued by the lack of ideal target antigens that are both absolutely tumor specific and homogeneously expressed. We show that multi-antigen prime-and-kill recognition circuits provide flexibility and precision to overcome these challenges in the context of glioblastoma. A synNotch receptor that recognizes a specific priming antigen, such as the heterogeneous but tumor-specific glioblastoma neoantigen epidermal growth factor receptor splice variant III (EGFRvIII) or the central nervous system (CNS) tissue-specific antigen myelin oligodendrocyte glycoprotein (MOG), can be used to locally induce expression of a CAR. This enables thorough but controlled tumor cell killing by targeting antigens that are homogeneous but not absolutely tumor specific. Moreover, synNotch-regulated CAR expression averts tonic signaling and exhaustion, maintaining a higher fraction of the T cells in a naïve/stem cell memory state. In immunodeficient mice bearing intracerebral patient-derived xenografts (PDXs) with heterogeneous expression of EGFRvIII, a single intravenous infusion of EGFRvIII synNotch-CAR T cells demonstrated higher antitumor efficacy and T cell durability than conventional constitutively expressed CAR T cells, without off-tumor killing. T cells transduced with a synNotch-CAR circuit primed by the CNS-specific antigen MOG also exhibited precise and potent control of intracerebral PDX without evidence of priming outside of the brain. In summary, by using circuits that integrate recognition of multiple imperfect but complementary antigens, we improve the specificity, completeness, and persistence of T cells directed against glioblastoma, providing a general recognition strategy applicable to other solid tumors.

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Ozaki, S., and J. A. Berzofsky. "Antibody conjugates mimic specific B cell presentation of antigen: relationship between T and B cell specificity." Journal of Immunology 138, no. 12 (June 15, 1987): 4133–42. http://dx.doi.org/10.4049/jimmunol.138.12.4133.

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Abstract We developed antibody conjugates by covalently coupling antibodies against mouse mu-chain and monoclonal antibodies against nominal antigen, myoglobin, as a tool for antigen presentation and as a model of specific presentation of antigen by antigen-specific B cells and T-B interaction. In the presence of the antibody conjugates, myoglobin-specific Iad-restricted cloned T cells proliferated at 1000-fold lower concentration of myoglobin than the stimulatory concentration without the conjugates. This enhanced presentation was observed only when Iad spleen cells were 1000 R-irradiated but not 3300 R-irradiated, consistent with B cell presentation. The simple mixture of each component of the conjugates had no enhancement effects. The conjugates per se had no mitogenic effects on either splenic B cells or the cloned T cells at concentrations employed for antigen presentation. The conjugates reduced the number of antigen-presenting cells required for the maximal response but did not change the kinetics of response. The enhanced presentation by the conjugates required a genetically restricted interaction with B cells. Antigen specificity of the enhanced presentation was confirmed by using various T cell clones or lines with different antigen specificities and different conjugates constructed with monoclonal antibodies of known epitope specificity. The enhanced presentation was significantly inhibited by competition with exogenous mouse IgM or anti-mouse mu-chain but was not significantly inhibited by monoclonal antibodies against Fc receptor. Thus, conjugate-coated B cells serve as models for myoglobin-specific B cells in that they can take up specific antigens at extremely low concentration and can present the antigen to specific T cells. This model system can be applied to any antigen and any species without the need to develop antigen-specific B cell clones, which is not yet possible for most antigens and species of experimental animals. This system allowed us to investigate the relationship between T cell epitope and B cell epitope when these cells interact with each other in an antigen-specific and Ia-restricted manner. Experiments using antibody conjugates of different monoclonal antibodies against myoglobin and various myoglobin-specific cloned T cells of known antigen specificity revealed that there are some particular combinations in which much more limited enhancement of antigen presentation is observed.(ABSTRACT TRUNCATED AT 400 WORDS)

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Hansburg, D., and E. Appella. "The sites of antigen-T cell and antigen-MHC interactions overlap." Journal of Immunology 135, no. 6 (December 1, 1985): 3712–18. http://dx.doi.org/10.4049/jimmunol.135.6.3712.

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Abstract The immune responses of B10.A and B10.A(3R) strains of mice to a synthetic variant of moth cytochrome c 86-103 were compared, and an immune response difference between the two strains was found. When T cell hybridomas were made from both strains it was found that the responsive T cells showed degenerate MHC restriction. The hybridomas from B10.A(3R) mice consistently showed a specificity pattern, when tested with allogeneic B10.A APC, different from that seen when syngeneic B10.A(3R) APC were used. The difference in the immune responses of the two strains of mice could be attributed to this APC-expressed specificity. The results were analyzed to determine whether the portion of the antigen that effected T cell memory (the epitope) and the portion that effected APC-expressed specificity (the agretope) were independent. It was found that a) these sites overlap and b) the APC-expressed specificity (i.e., the specificity of agretope recognition) was dependent on the T cell clonotype. This implies that the agretope is not an independent parameter in the process of MHC-restricted antigen recognition. Therefore its employment as an explanation for various phenomena will be limited by the likelihood of circularity.

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Priest, Jeffrey W., James P. Kwon, Delynn M. Moss, Jacquelin M. Roberts, Michael J. Arrowood, Mark S. Dworkin, Dennis D. Juranek, and Patrick J. Lammie. "Detection by Enzyme Immunoassay of Serum Immunoglobulin G Antibodies That Recognize SpecificCryptosporidium parvum Antigens." Journal of Clinical Microbiology 37, no. 5 (1999): 1385–92. http://dx.doi.org/10.1128/jcm.37.5.1385-1392.1999.

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Human infection with Cryptosporidium parvum usually elicits characteristic immunoglobulin G (IgG), IgA, and IgM antibody responses against two sporozoite surface antigens with apparent molecular masses of approximately 27 and 17 kDa. We have determined that these two antigens are actually complex families of related antigens. We have developed two new enzyme-linked immunosorbent assays (ELISAs) for the detection and quantitation of serum IgG antibodies against both antigens. The assays utilize a recombinant form of the 27-kDa antigen and a partially purified native fraction isolated from sonicated whole oocysts that contains 17-kDa antigen. An immunoblot assay previously developed in our laboratory served as the reference, or “gold standard,” seroassay for the assessment of the new ELISAs. Positive responses with the recombinant-27-kDa-antigen ELISA were correlated with the immunoblot results for the 27-kDa antigen, with a sensitivity and specificity of 90 and 92%, respectively. Similarly, positive responses with the partially purified native-17-kDa-antigen ELISA correlated with the immunoblot results for the 17-kDa antigen, with a sensitivity and specificity of 90 and 94%, respectively. For both ELISAs the median IgG antibody levels for serum sets collected during outbreaks of waterborne C. parvum infection were at least 2.5-fold higher than the levels determined for a nonoutbreak set. Using the immunoblot as the “gold standard,” the new ELISAs were more specific and, in the case of the 27-kDa-antigen ELISA, more sensitive than the crude oocyst antigen ELISA currently in use. These assays will be useful in future epidemiologic studies.

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Bangham, C. R., P. J. Openshaw, L. A. Ball, A. M. King, G. W. Wertz, and B. A. Askonas. "Human and murine cytotoxic T cells specific to respiratory syncytial virus recognize the viral nucleoprotein (N), but not the major glycoprotein (G), expressed by vaccinia virus recombinants." Journal of Immunology 137, no. 12 (December 15, 1986): 3973–77. http://dx.doi.org/10.4049/jimmunol.137.12.3973.

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Abstract The viral antigens recognized by cytotoxic T cells (CTL) have not been defined in most viruses infecting mouse or man. Natural or artificial virus recombinants can be used to determine the antigen specificity of CTL directed against viruses with segmented genomes, such as influenza, but this technique is more difficult to apply to the study of unsegmented viruses. We describe here the use of recombinant vaccinia viruses, containing cDNA corresponding to either the nucleoprotein (N) gene or the major surface glycoprotein (G) gene of human respiratory syncytial virus (RSV), to examine the antigen specificity of anti-RSV cytotoxic T cells from humans and mice. The results demonstrate that the RSV N protein is one of the target antigens for CTL in man and mouse, whereas the G protein was not recognized and can at best represent a minor target antigen for CTL.

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Tiegs, S. L., D. M. Russell, and D. Nemazee. "Receptor editing in self-reactive bone marrow B cells." Journal of Experimental Medicine 177, no. 4 (April 1, 1993): 1009–20. http://dx.doi.org/10.1084/jem.177.4.1009.

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A central paradigm of immunology is clonal selection: lymphocytes displaying clonally distributed antigen receptors are generated and subsequently selected by antigen for growth or elimination. Here we show that in mice transgenic for anti-H-2Kk,b antibody genes, in which a homogeneous clone of developing B cells can be analyzed for the outcome of autoantigen encounter, surface immunoglobulin M+/idiotype+ immature B cells binding to self-antigens in the bone marrow are induced to alter the specificity of their antigen receptors. Transgenic bone marrow B cells encountering membrane-bound Kb or Kk proteins modify their receptors by expressing the V(D)J recombinase activator genes and assembling endogenously encoded immunoglobulin light chain variable genes. This (auto)antigen-directed change in the specificity of newly generated lymphocytes is termed receptor editing.

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Wardhani, Puspa, Prihatini Prihatini, and Probohoesodo M.Y. "KEMAMPUAN UJI TABUNG WIDAL MENGGUNAKAN ANTIGEN IMPORT DAN ANTIGEN LOKAL." INDONESIAN JOURNAL OF CLINICAL PATHOLOGY AND MEDICAL LABORATORY 12, no. 1 (March 13, 2018): 31. http://dx.doi.org/10.24293/ijcpml.v12i1.838.

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Despite of its higher specificity than Widal-slide test, Widal-tube test is not widely used by medical laboratories because it is not practical and each laboratory has to produce their own antigens. The Laboratory must have sufficient microbiology equipments and reagents to produce antigens. REMEL® provides ‘ready for use’ antigens to perform Widal-tube test. To Compare and correlate Widal-tube test using REMEL® imported antigens and local antigens (produced by lab. Clinical pathology Dr. Soetomo hospital). The samples were tested by Widal-tube test, using REMEL® and local antigens, comparing Salmonella typhi (ST) O antigen, ST H antigen, S. paratyphi (SP) A H antigen, and SP B H antigen for each method, with twofold dilution from 1/40 until 1/1280. The number of samples was 55. The results are defined as pathologic (above cut-off value) and non pathologic (below cut-off value). REMEL® ST O antigen had a significant correlation to local antigens (r = 0.665, p < 0.01). REMEL® ST H antigen also had a significant correlation to local antigen (r = 0.671, p < 0.01), REMEL® SP B H has no significant correlation to local antigen (r = 0.389, p < 0.01). All samples (55) showed negative results (non pathologic) using SPA H local antigen. When using REMEL® SPA H antigen, 51 were non pathologic and 4 were pathologic. Widal-tube test using REMEL® antigens has significant correlation with local antigens so it might be considered to be used for diagnosing typhoid fever.

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Spence, Allyson, Whitney Purtha, Janice Tam, Shen Dong, Youmin Kim, Chia-Hsin Ju, Teague Sterling, et al. "Revealing the specificity of regulatory T cells in murine autoimmune diabetes." Proceedings of the National Academy of Sciences 115, no. 20 (April 30, 2018): 5265–70. http://dx.doi.org/10.1073/pnas.1715590115.

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Regulatory T cells (Tregs) control organ-specific autoimmunity in a tissue antigen-specific manner, yet little is known about their specificity in a natural repertoire. In this study, we used the nonobese diabetic (NOD) mouse model of autoimmune diabetes to investigate the antigen specificity of Tregs present in the inflamed tissue, the islets of Langerhans. Compared with Tregs present in spleen and lymph node, Tregs in the islets showed evidence of antigen stimulation that correlated with higher proliferation and expression of activation markers CD103, ICOS, and TIGIT. T cell receptor (TCR) repertoire profiling demonstrated that islet Treg clonotypes are expanded in the islets, suggesting localized antigen-driven expansion in inflamed islets. To determine their specificity, we captured TCRαβ pairs from islet Tregs using single-cell TCR sequencing and found direct evidence that some of these TCRs were specific for islet-derived antigens including insulin B:9–23 and proinsulin. Consistently, insulin B:9–23 tetramers readily detected insulin-specific Tregs in the islets of NOD mice. Lastly, islet Tregs from prediabetic NOD mice were effective at preventing diabetes in Treg-deficient NOD.CD28−/− recipients. These results provide a glimpse into the specificities of Tregs in a natural repertoire that are crucial for opposing the progression of autoimmune diabetes.

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Davies, J. D., D. H. Wilson, and D. B. Wilson. "Generation of T cells with lytic specificity for atypical antigens. III. Priming F1 animals with antigen-bearing cells also having reactivity for host alloantigens allows for potent lytic T cell responses." Journal of Experimental Medicine 173, no. 4 (April 1, 1991): 841–47. http://dx.doi.org/10.1084/jem.173.4.841.

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Here, we explore the conditions required for generating two different highly potent F1 antiparental killer cell populations to unusual antigens in rats. The first, L/DA anti-DA, has lytic specificity for two antigen systems: MTA, a mitochondrial antigen expressed on DA and DA Lewis (L) target cells restricted by RT1A class I molecules; and H, an antigen that maps to the class I-like RT1C region and is present only on parental target cells from donors homozygous at the major histocompatibility complex. The second killer population is generated in the reciprocal DA/L anti-DA combination and has lytic specificity only for the H antigen system. We show that the killer cells are T cells, and that generation of these F1 cytotoxic T lymphocytes (CTL) requires an in vivo priming step in which it is essential that the inoculated parental cells bear the relevant target antigens and possess alloreactivity for F1 host antigens. The requirement for alloreactivity and antigen on the same priming cell population suggests that these potent lytic responses depend on a situation akin to a hapten-carrier effect that bypasses otherwise ineffective helper responses by the host to these unusual antigens. Restimulation of F1 lymphocytes in culture is also necessary, requiring the presence of antigen on irradiated lymphoblast stimulator cells, but alloreactivity to responder cell antigens is not necessary; normal, nonactivated lymph node cells are completely ineffective as stimulators. For effective lysis, the target cells need not possess the potential for alloreactivity to responder F1 CTL. We also demonstrate in a preliminary way additional antigen systems defined by killer populations raised with other F1 antiparental strain combinations.

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Faherty, D. A., D. R. Johnson, and M. Zauderer. "Origin and specificity of autoreactive T cells in antigen-induced populations." Journal of Experimental Medicine 161, no. 6 (June 1, 1985): 1293–301. http://dx.doi.org/10.1084/jem.161.6.1293.

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We have characterized the major histocompatibility complex (MHC) specificity of autoreactive T cell clones arising from diverse donors after immunization with different antigens. The MHC fine specificity of autoreactive T cells for unique F1 hybrid determinants of BALB.K X BALB.B F1, and for the mutant I-Ab determinants of the B6.C-H-2bm12 (bm 12) strain is similar to that previously described for antigen-specific T cells. We find, furthermore, that the MHC specificity of autoreactive T cell clones selected from primed populations grown in the absence of Con A-stimulated supernatant factors reflects the predominant MHC restriction specificity of T cells specific for the immunogen. Thus, I-E subregion-specific autoreactive T cells are detected at a much higher frequency after immunization with the I-E-restricted antigen, GL (terpolymer of glutamic acid, lysine, and phenylalanine), than with the predominantly I-A-restricted antigen, keyhole limpet hemocyanin (KLH). These experiments strongly suggest that some autoreactive T cells are derived from antigen-stimulated precursors. This result contrasts with that obtained when autoreactive T cells are selected in bulk cultures, or in the presence of exogenous T cell factors. We conclude that, under optimal conditions, most autoreactive T cells are recruited from a relatively stable pool of predominantly I-A-specific precursors. Autoreactive precursors in this pool might themselves derive from previous antigenic stimulation, or be of independent origin.

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Fonseca, Bruna P. F., Christiane F. S. Marques, Lílian D. Nascimento, Marcelle B. Mello, Leila B. R. Silva, Nara M. Rubim, Leonardo Foti, Edimilson D. Silva, Antonio G. P. Ferreira, and Marco A. Krieger. "Development of a Multiplex Bead-Based Assay for Detection of Hepatitis C Virus." Clinical and Vaccine Immunology 18, no. 5 (February 23, 2011): 802–6. http://dx.doi.org/10.1128/cvi.00265-10.

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ABSTRACTHepatitis C virus (HCV) infection is a major burden to public health worldwide, affecting approximately 3% of the human population. Although HCV detection is currently based on reliable tests, the field of medical diagnostics has a growing need for inexpensive, accurate, and quick high-throughput assays. By using the recombinant HCV antigens NS3, NS4, NS5, and Combined, we describe a new bead-based multiplex test capable of detecting HCV infection in human serum samples. The first analysis, made in a singleplex format, showed that each antigen coupled to an individual bead set presented high-level responses for anti-HCV-positive reference serum pools and lower-level responses for the HCV-negative pools. Our next approach was to determine the sensitivity and specificity of each antigen by testing 93 HCV-positive and 93 HCV-negative sera. When assayed in the singleplex format, the NS3, NS4, and NS5 antigens presented lower sensitivity values (50.5%, 51.6%, and 55.9%, respectively) than did the Combined antigen, which presented a sensitivity of 93.5%. All antigens presented 100% specificity. These antigens were then multiplexed in a 4-plex assay, which resulted in increased sensitivity and specificity values, performing with 100% sensitivity and 100% specificity. The positive and negative predictive values for the 4-plex assay were 100%. Although preliminary, this 4-plex assay showed robust results that, aligned with its small-sample-volume requirements and also its cost- and time-effectiveness, make it a reasonable alternative to tests currently used for HCV screening of potentially infected individuals.

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Grant, Ethan P., Massimo Degano, Jean-Pierre Rosat, Steffen Stenger, Robert L. Modlin, Ian A. Wilson, Steven A. Porcelli, and Michael B. Brenner. "Molecular Recognition of Lipid Antigens by T Cell Receptors." Journal of Experimental Medicine 189, no. 1 (January 4, 1999): 195–205. http://dx.doi.org/10.1084/jem.189.1.195.

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The T cell antigen receptor (TCR) mediates recognition of peptide antigens bound in the groove of major histocompatibility complex (MHC) molecules. This dual recognition is mediated by the complementarity-determining residue (CDR) loops of the α and β chains of a single TCR which contact exposed residues of the peptide antigen and amino acids along the MHC α helices. The recent description of T cells that recognize hydrophobic microbial lipid antigens has challenged immunologists to explain, in molecular terms, the nature of this interaction. Structural studies on the murine CD1d1 molecule revealed an electrostatically neutral putative antigen-binding groove beneath the CD1 α helices. Here, we demonstrate that α/β TCRs, when transferred into TCR-deficient recipient cells, confer specificity for both the foreign lipid antigen and CD1 isoform. Sequence analysis of a panel of CD1-restricted, lipid-specific TCRs reveals the incorporation of template-independent N nucleotides that encode diverse sequences and frequent charged basic residues at the V(D)J junctions. These sequences permit a model for recognition in which the TCR CDR3 loops containing charged residues project between the CD1 α helices, contacting the lipid antigen hydrophilic head moieties as well as adjacent CD1 residues in a manner that explains antigen specificity and CD1 restriction.

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Borrok, M. Jack, Yonghai Li, Paul B. Harvilla, Bharathikumar Vellalore Maruthachalam, Ninkka Tamot, Christine Prokopowitz, Jun Chen, et al. "Conduit CAR: Redirecting CAR T-Cell Specificity with A Universal and Adaptable Bispecific Antibody Platform." Cancer Research Communications 2, no. 3 (March 2022): 146–57. http://dx.doi.org/10.1158/2767-9764.crc-21-0150.

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The success of chimeric antigen receptor (CAR) T-cell therapy against hematologic malignancies has altered the treatment paradigm for patients with these diseases. Nevertheless, the occurrence of relapse due to antigen escape or heterogeneous antigen expression on tumors remains a challenge for first-generation CAR T-cell therapies as only a single tumor antigen can be targeted. To address this limitation and to add a further level of tunability and control to CAR T-cell therapies, adapter or universal CAR T-cell approaches use a soluble mediator to bridge CAR T cells with tumor cells. Adapter CARs allow simultaneous or sequential targeting of multiple tumor antigens, control of immune synapse geometry, dose control, and the potential for improved safety. Herein, we described a novel CAR T-cell adapter platform that relies on a bispecific antibody (BsAb) targeting both a tumor antigen and the GGGGS (G4S) linker commonly used in single-chain Fv (ScFv) domains expressed on CAR T-cell surfaces. We demonstrated that the BsAb can bridge CAR T cells to tumor cells and potentiate CAR T-cell activation, proliferation, and tumor cell cytolysis. The cytolytic activity of CAR T-cells was redirected to different tumor antigens by changing the BsAb in a dose-dependent manner. This study highlights the potential of G4S-displaying CAR T cells to be redirected to engage alternative tumor-associated antigens (TAA). Significance: New approaches are needed to address relapsed/refractory disease and manage potential toxicities associated with CAR T-cell therapy. We describe an adapter CAR approach to redirect CAR T cells to engage novel TAA-expressing cells via a BsAb targeting a linker present on many clinical CAR T-cell therapeutics. We anticipate the use of such adapters could increase CAR T-cell efficacy and reduce potential CAR-associated toxicities.

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Grab, Dennis J., Anuj Sharma, Ian Burbulis, Axel T. Lehrer, Vivek Nerurkar, and Stefan Magez. "Nanobody LAMPoles: Novel tools for dengue virus and Zika virus diagnosis." Journal of Immunology 204, no. 1_Supplement (May 1, 2020): 82.24. http://dx.doi.org/10.4049/jimmunol.204.supp.82.24.

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Abstract Detection of antibodies by ELISA for verifying exposure to dengue virus (DENV) and Zika virus (ZIKV) has been a challenge. Point-of-care (POC) diagnostics with detection of very low concentrations of viral antigens would improve critical disease staging and surveillance to reduce morbidity and mortality. LAMPoles are protein-DNA hybrids where a ‘DNA barcode’ is covalently linked to a single site on a protein. Recombinant camelid nanobodies (Nb), which are variable region of the heavy chain antigen binding domain (VHH), can be tailored to bind almost any molecular target to maximize assay sensitivity and specificity. LAMPole fusions displaying Nb that bind ZIKV and DENV antigens will improve the sensitivity and specificity of virus antigen measurement at the POC. Llama were vaccinated with recombinant DENV envelope or ZIKV NS1 proteins and VHH phagemid libraries constructed and screened for DENV and ZIKV antigen-specific Nb. For DENV 70 full-length Nb were identified, belonging to 26 different CDR3 groups. For ZIKV 63 full-length anti-ZIKV Nb were identified, belonging to 42 different CDR3 groups. Nb screened by surface plasmon resonance spectroscopy with Koff kinetics in the 10−3 sec range were conjugated to chalcone synthase specific DNA elements using psoralen-based photocross-linkers. In a pilot experiment, LAMP targeting the CHS DNA tail of one Nb-LAMPole detected less than 10 fg of Nb-LAMPole protein. Nb-LAMPole recognized DENV-2 E-protein antigen in sandwich ELISA and in DENV-2 infected cells by immunofluorescence. We assert that LAMPole fusions displaying Nb that bind viral antigens may improve the sensitivity and specificity of DENV and ZIKV antigen detection that will facilitate markedly improved POC diagnosis.

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Qader, Staar, and Sanarya Tawfiq. "The role of IFN-gamma in Humoral immune response for HCMV antigens among pregnant women." Al-Kitab Journal for Pure Sciences 3, no. 2 (October 17, 2020): 247–58. http://dx.doi.org/10.32441/kjps.03.02.p23.

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Background: Human cytomegalovirus (HCMV) is a highly host-specific virus belongs to the βherpesvirus subfamily, which is a leading cause of congenital infections. The immune cytokines such as Interferons-gama (IFN- ) may have direct inhibitory effects on HCMV replication and control of viral infections. Aim of the study: This research aims at determining the specificity of anti-HCMV antibodies for different HCMV antigens in relation to serum INF- levels. Materials & Methods: A cross sectional study was carried out in Kirkuk governorate from April 2018 to June 2019. The number of pregnant women understudy was 400 women presented to some private medical laboratories. The pregnant women were examined for the seroprevalence of HCMVIgM and IgG by using ECLIA technique then their specificities determined for different HCMV antigens by using line immune assay, In addition to estimation the level of serum INF- levels by using ELISA technique. Results: The rate of HCMV-IgG , HCMV-IgM and both HCMV-IgG and IgM at the same time were 288(72 %), 32(8%) and 18(4.5%) respectively. Regarding the specificity of the determined HCMVIgM to various HCMV antigens (IE1, CM2, p150, p65, gB1 and gB2), the highest rate of HCMVIgG was 96.25% specific for gB1 antigen, while highest rate of HCMV-IgM were 96.87% specific gB1 and p150 antigen. Considering the specificity of these antibodies for the examined antigens in relation to serum INF- levels, the highest of pregnant women with increased INF- level had antibodies for IE1 antigen. Conclusions: There was significant relation of the serum INF- level with specificity of anti-HCMV antibodies to divers HCMV antigens.

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Qader, Staar Mohammed, and Sanarya Kamal Tawfiq. "The role of IFN-gamma in Humoral immune response for HCMV antigens among pregnant women." Al-Kitab Journal for Pure Sciences 3, no. 2 (August 18, 2023): 247–58. http://dx.doi.org/10.32441/kjps.03.02.p23r.

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Background: Human cytomegalovirus (HCMV) is a highly host-specific virus belongs to the β-herpesvirus subfamily, which is a leading cause of congenital infections. The immune cytokines such as Interferons-gama (IFN- ) may have direct inhibitory effects on HCMV replication and control of viral infections. Aim of the study: This research aims at determining the specificity of anti-HCMV antibodies for different HCMV antigens in relation to serum INF- levels. Materials & Methods: A cross sectional study was carried out in Kirkuk governorate from April 2018 to June 2019. The number of pregnant women understudy was 400 women presented to some private medical laboratories. The pregnant women were examined for the seroprevalence of HCMV-IgM and IgG by using ECLIA technique then their specificities determined for different HCMV antigens by using line immune assay, In addition to estimation the level of serum INF- levels by using ELISA technique. Results: The rate of HCMV-IgG , HCMV-IgM and both HCMV-IgG and IgM at the same time were 288(72 %), 32(8%) and 18(4.5%) respectively. Regarding the specificity of the determined HCMV-IgM to various HCMV antigens (IE1, CM2, p150, p65, gB1 and gB2), the highest rate of HCMV-IgG was 96.25% specific for gB1 antigen, while highest rate of HCMV-IgM were 96.87% specific gB1 and p150 antigen. Considering the specificity of these antibodies for the examined antigens in relation to serum INF- levels, the highest of pregnant women with increased INF- level had antibodies for IE1 antigen. Conclusions: There was significant relation of the serum INF- level with specificity of anti-HCMV antibodies to divers HCMV antigens.

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39

Dong, Shen, Daqi Xu, Jennifer Anne Bridge, Whitney Purtha, Allyson Spence, Danny Wells, Xiao hua Wang, Qizhi Tang, Mark S. Anderson, and Jeffrey A. Bluestone. "Antigen discovery for regulatory T cells (Tregs) in type-1 diabetes (T1D)." Journal of Immunology 200, no. 1_Supplement (May 1, 2018): 101.12. http://dx.doi.org/10.4049/jimmunol.200.supp.101.12.

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Abstract Antigen specific Tregs are more efficient than polyclonal Tregs in their suppressive capacity, which makes them attractive tools for further targeted tolerogenic therapy. Autoreactive T cells specificity has been well characterized in type 1-diabetes but little is known about autoreactive Treg specificity. Whether Tregs recognize the same tissue-specific self-antigens as autoreactive T cell, or they recognize different self-antigens to regulate local immune responses via bystander suppression is unclear. Our goal is to identify antigen specificity from enriched islet infiltrated Treg by using previously validated peptide-major histocompatibility complex (pMHC) library displayed on yeast. We first performed single cell TCR sequencing on Tregs from the pancreatic islet of 12 weeks old NOD mice. Data show an abundance of the TCR allele TRAV5D4 usage in islet infiltrated Tregs that has been characterized to target a primary insulin peptide. Moreover, we also performed single cell RNAseq together with TCR sequencing on islet infiltrated CD4+ T cells from a T1D patient from the Network for Pancreatic Organ Donors with Diabetes. We were able to identify enriched TCRs with Treg gene expression profile that will be used to screen for antigen recognition on a DR4 pMHC yeast library. New antigen identification for pancreatic islet-infiltrated Tregs will allow us to improve our understanding of Treg deficiencies in T1D and may lead us to design new immunosuppressive therapies.

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Kadival, G. V., S. D. Chaparas, and D. Hussong. "Characterization of serologic and cell-mediated reactivity of a 38-kDa antigen isolated from Mycobacterium tuberculosis." Journal of Immunology 139, no. 7 (October 1, 1987): 2447–51. http://dx.doi.org/10.4049/jimmunol.139.7.2447.

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Abstract An antigen of Mycobacterium tuberculosis with an m.w. of 38,000 has been isolated by affinity chromatography using a monoclonal antibody. This antibody bound only to an antigen found in M. tuberculosis and Mycobacterium bovis BCG. The specificity of the antigen was tested in a vertical study by immunodetection on western blots reacted with hyperimmune sera against M. tuberculosis, M. bovis, and 10 other Mycobacterium species. The antigen was detected only by antisera to M. tuberculosis and M. bovis. Specificity in cell-mediated immunity was tested by skin tests in guinea pigs sensitized with M. tuberculosis, Mycobacterium intracellulare, and Mycobacterium kansasii and by lymphocyte proliferation tests. The 38-kDa antigen induced positive skin test reactions regardless of the Mycobacterium species used to sensitize the animal. The ability of the 38-kDa antigen to sensitize for cell-mediated immunity was tested by injecting mice with the 38-kDa antigen and challenging their lymphocytes in vitro with various mycobacterial antigens. Lymphocyte proliferation was observed in the presence of 38-kDa antigen, M. tuberculosis sonicate antigen, and tuberculin purified protein derivative and to M. kansasii and M. intracellulare. The 38-kDa antigen may contain a specific epitope detected by serology, but also contains epitopes that are cross-reactive for cellular immunity.

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Libero, Gennaro De. "Antigen Specificity of Human TCR γδ Cells." Open Immunology Journal 7, no. 1 (June 13, 2014): 119–26. http://dx.doi.org/10.2174/1874226200902010119.

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De Libero, Gennaro. "Antigen Specificity of Human TCR γδ Cells." Open Immunology Journal 2, no. 2 (October 28, 2009): 119–26. http://dx.doi.org/10.2174/1874226200902020119.

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Børmer, O. P. "Immunoassays for Carcinoembryonic antigen: Specificity and interferences." Scandinavian Journal of Clinical and Laboratory Investigation 53, no. 1 (January 1993): 1–9. http://dx.doi.org/10.3109/00365519309092525.

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Coombs, Gary S., Robert C. Bergstrom, Jean-Luc Pellequer, Scott I. Baker, Marc Navre, Matthew M. Smith, John A. Tainer, Edwin L. Madison, and David R. Corey. "Substrate specificity of prostate-specific antigen (PSA)." Chemistry & Biology 5, no. 9 (September 1998): 475–88. http://dx.doi.org/10.1016/s1074-5521(98)90004-7.

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Day, M. J. "Antigen specificity in canine autoimmune haemolytic anaemia." Veterinary Immunology and Immunopathology 69, no. 2-4 (August 1999): 215–24. http://dx.doi.org/10.1016/s0165-2427(99)00055-0.

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Tenforde, MW, N. Longley, DB Meya, DR Boulware, G. Meintjes, I. Goercke, TS Harrison, and JN Jarvis. "Poor specificity of urinary cryptococcal antigen testing." HIV Medicine 19, no. 2 (September 7, 2015): e47-e48. http://dx.doi.org/10.1111/hiv.12319.

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COLLINS, D. A., and B. E. BOURKE. "Antigen Specificity of ANCA in Systemic Vasculitis." Rheumatology 34, no. 4 (1995): 394. http://dx.doi.org/10.1093/rheumatology/34.4.394.

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Anderson, Marc O., Lisa Y. Wu, Nicholas M. Santiago, Jamie M. Moser, Jennifer A. Rowley, Erin S. D. Bolstad, and Clifford E. Berkman. "Substrate specificity of prostate-specific membrane antigen." Bioorganic & Medicinal Chemistry 15, no. 21 (November 2007): 6678–86. http://dx.doi.org/10.1016/j.bmc.2007.08.006.

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Burbelo, Peter D., Hannah P. Leahy, Sandra Groot, Lisa R. Bishop, Wendell Miley, Michael J. Iadarola, Denise Whitby, and Joseph A. Kovacs. "Four-Antigen Mixture Containing V-Cyclin for Serological Screening of Human Herpesvirus 8 Infection." Clinical and Vaccine Immunology 16, no. 5 (March 4, 2009): 621–27. http://dx.doi.org/10.1128/cvi.00474-08.

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ABSTRACT Improved diagnostic reagents and testing are currently needed for the serological detection of human herpesvirus 8 (HHV-8) infections. We evaluated the luciferase immunoprecipitation systems (LIPS) for profiling antibody responses to a panel of HHV-8 proteins for diagnosis of Kaposi sarcoma (KS)-infected individuals. Using a pilot serum set, LIPS detected robust antibody responses to several known antigens, and a screen of 14 additional HHV-8 proteins identified v-cyclin as a potentially new diagnostic antigen. In evaluating a training-serum set, a four-antigen panel (K8.1, v-cyclin, ORF65, and a LANA fragment) was found to provide sufficient information for diagnosis. Analysis of a validation serum set using the combined results from these four separate antigen tests showed 100% sensitivity and 100% specificity. Furthermore, a LIPS format using a mixture of the four antigens, which simplifies data collection and analysis, closely matched the diagnostic performance of the combined separate tests (R = 0.95). This four-antigen mixture format analyzed with the validation serum set also showed 100% sensitivity and 100% specificity but was not statistically different from two separate enzyme-linked immunosorbent assays (94% sensitivity and 100% specificity) using baculovirus-produced LANA and bacterially produced K8.1. Heat map analysis of KS patient antibody titers revealed marked heterogeneity in humoral responses to this four-antigen panel. Overall, the LIPS assay showed 97% sensitivity, and positive anti-v-cyclin antibodies were detected in approximately 75% of the KS sera. These results suggest that LIPS screening using an antigen mixture is a sensitive and high-throughput method for serological screening of HHV-8 infection in individuals with KS.

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Peters, Iain R., Chris R. Helps, Timothy J. Gruffydd-Jones, Michael J. Day, and Séverine Tasker. "Antigen Specificity of the Humoral Immune Response to Mycoplasma haemofelis Infection." Clinical and Vaccine Immunology 17, no. 8 (June 2, 2010): 1238–43. http://dx.doi.org/10.1128/cvi.00136-10.

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ABSTRACT The aim of the present study was to characterize the antigenic specificity of the humoral immune response made by cats infected with the feline hemoplasma, Mycoplasma haemofelis. A crude M. haemofelis antigen preparation was prepared from red blood cells (RBCs) collected from a cat at the time of a high level of bacteremia. Plasma samples were collected from six cats before and after experimental infection with M. haemofelis, with regular sampling being performed from 15 to 149 or 153 days postinfection (dpi). Preinfection RBC membrane ghosts were prepared from these six cats and used to identify erythrocyte proteins that may have contaminated the M. haemofelis antigen preparation. The M. haemofelis antigen preparation comprised 11 protein bands. The immunodominant bands on Western blotting with infected cat plasma had molecular masses of 78, 68, 60, 48, and 38 kDa. Most cats (n = 5) had plasma antibody that reacted with at least one band (always including the one of 68 kDa) at 15 dpi, and all cats were seroreactive by 29 dpi. The maximum number of antibodies from an individual animal specific for an antigen was identified in plasma collected from 57 to 99 dpi. Contamination of the M. haemofelis antigen preparation with RBC membrane proteins was observed. The contaminating RBC proteins had molecular masses of from 71 to 72 kDa (consistent with band 4.2) and 261 and 238 kDa (consistent with spectrin), and these were recognized by all plasma samples. A range of M. haemofelis antigens is recognized by cats infected experimentally with the organism. These represent possible targets for immunoassays, but care must be taken to prevent false-positive results due to host protein contamination.

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Journal articles on the topic 'Antigen specificity'

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