Components of the antigen processing and presentation pathway revealed by gene expression microarray analysis of following B cell antigen receptor (BCR) stimulation
Data Interpretation, Statistical
Gene Expression Profiling
Oligonucleotide Array Sequence Analysis
Protein Interaction Mapping
Receptors, Antigen, B-Cell
Permanent link to this recordhttp://hdl.handle.net/20.500.12613/5635
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AbstractBackground: Activation of naïve B lymphocytes by extracellular ligands, e.g. antigen, lipopolysaccharide (LPS) and CD40 ligand, induces a combination of common and ligand-specific phenotypic changes through complex signal transduction pathways. For example, although all three of these ligands induce proliferation, only stimulation through the B cell antigen receptor (BCR) induces apoptosis in resting splenic B cells. In order to define the common and unique biological responses to ligand stimulation, we compared the gene expression changes induced in normal primary B cells by a panel of ligands using cDNA microarrays and a statistical approach, CLASSIFI (Cluster Assignment for Biological Inference), which identifies significant co-clustering of genes with similar Gene Ontology™ annotation. Results: CLASSIFI analysis revealed an overrepresentation of genes involved in ion and vesicle transport, including multiple components of the proton pump, in the BCR-specific gene cluster, suggesting that activation of antigen processing and presentation pathways is a major biological response to antigen receptor stimulation. Proton pump components that were not included in the initial microarray data set were also upregulated in response to BCR stimulation in follow up experiments. MHC Class II expression was found to be maintained specifically in response to BCR stimulation. Furthermore, ligand-specific internalization of the BCR, a first step in B cell antigen processing and presentation, was demonstrated. Conclusion: These observations provide experimental validation of the computational approach implemented in CLASSIFI, demonstrating that CLASSIFI-based gene expression cluster analysis is an effective data mining tool to identify biological processes that correlate with the experimental conditional variables. Furthermore, this analysis has identified at least thirty-eight candidate components of the B cell antigen processing and presentation pathway and sets the stage for future studies focused on a better understanding of the components involved in and unique to B cell antigen processing and presentation. © 2006 Lee et al; licensee BioMed Central Ltd.
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Has partBMC Bioinformatics
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Distinctive germline expression of class i human leukocyte antigen (HLA) alleles and DRB1 heterozygosis predict the outcome of patients with non-small cell lung cancer receiving PD-1/PD-L1 immune checkpoint blockadeCorreale, P; Saladino, RE; Giannarelli, D; Giannicola, R; Agostino, R; Staropoli, N; Strangio, A; Del Giudice, T; Nardone, V; Altomonte, M; Pastina, P; Tini, P; Falzea, AC; Imbesi, N; Arcati, V; Romeo, G; Caracciolo, D; Luce, A; Caraglia, M; Giordano, A; Pirtoli, L; Necas, A; Amler, E; Barbieri, V; Tassone, P; Tagliaferri, P; Giordano, Antonio|0000-0002-5959-016X (2020-06-17)© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. Background Nivolumab is a human monoclonal antibody against programmed cell death receptor-1 (PD-1) able to rescue quiescent tumor infiltrating cytotoxic T lymphocytes (CTLs) restoring their ability to kill target cells expressing specific tumor antigen-derived epitope peptides bound to homologue human leukocyte antigen (HLA) molecules. Nivolumab is currently an active but expensive therapeutic agent for metastatic non-small cell lung cancer (mNSCLC), producing, in some cases, immune-related adverse events (irAEs). At the present, no reliable biomarkers have been validated to predict either treatment response or adverse events in treated patients. Methods We performed a retrospective multi-institutional analysis including 119 patients with mNSCLC who received PD-1 blockade since November 2015 to investigate the predictive role of germinal class I HLA and DRB1 genotype. We investigated the correlation among patients' outcome and irAEs frequency with specific HLA A, B, C and DRB1 alleles by reverse sequence-specific oligonucleotide (SSO) DNA typing. Results A poor outcome in patients negative for the expression of two most frequent HLA-A alleles was detected (HLA: HLA-A∗01 and or A∗02; progression-free survival (PFS): 7.5 (2.8 to 12.2) vs 15.9 (0 to 39.2) months, p=0.01). In particular, HLA-A∗01-positive patients showed a prolonged PFS of 22.6 (10.2 to 35.0) and overall survival (OS) of 30.8 (7.7 to 53.9) months, respectively. We also reported that HLA-A and DRB1 locus heterozygosis (het) were correlated to a worse OS if we considered het in the locus A; in reverse, long survival was correlated to het in DRB1. Conclusions This study demonstrate that class I and II HLA allele characterization to define tumor immunogenicity has relevant implications in predicting nivolumab efficacy in mNSCLC and provide the rationale for further prospective trials of cancer immunotherapy.
Tcr triggering by pMHC ligands tethered on surfaces via poly(ethylene glycol) depends on polymer lengthZhengyu, M; David, NLB; Sharon, ML; Kim, AS; Michael, LK; Dennis, ED; Terri, HF (2014-11-10)© 2014 Ma et al. Antigen recognition by T cells relies on the interaction between T cell receptor (TCR) and peptide-major histocompatibility complex (pMHC) at the interface between the T cell and the antigen presenting cell (APC). The pMHC-TCR interaction is two-dimensional (2D), in that both the ligand and receptor are membrane-anchored and their movement is limited to 2D diffusion. The 2D nature of the interaction is critical for the ability of pMHC ligands to trigger TCR. The exact properties of the 2D pMHC-TCR interaction that enable TCR triggering, however, are not fully understood. Here, we altered the 2D pMHCTCR interaction by tethering pMHC ligands to a rigid plastic surface with flexible poly(ethylene glycol) (PEG) polymers of different lengths, thereby gradually increasing the ligands' range of motion in the third dimension. We found that pMHC ligands tethered by PEG linkers with long contour length were capable of activating T cells. Shorter PEG linkers, however, triggered TCR more efficiently. Molecular dynamics simulation suggested that shorter PEGs exhibit faster TCR binding onrates and off-rates. Our findings indicate that TCR signaling can be triggered by surface-tethered pMHC ligands within a defined 3D range of motion, and that fast binding rates lead to higher TCR triggering efficiency. These observations are consistent with a model of TCR triggering that incorporates the dynamic interaction between T cell and antigen-presenting cell.
The Role of Gamma-Delta TCR+ T-cells in the Pathogenesis of Systemic SclerosisPlatsoucas, Chris D.; Tsygankov, Alexander Y.; Monestier, Marc; Oleszak, Emilia; Ashby, Barrie; Chong, Parkson Lee-Gau; Myers, Allen R. (Temple University. Libraries, 2008)The human gamma-delta (gd) TCR+ T-cell subset may undergo specific antigen-driven activation and clonal expansion, in the context of systemic sclerosis (SSc) pathogenesis. The purpose of this study was; 1) To determine whether gd TCR+ T-cells are clonally expanded in skin biopsies and peripheral blood from patients with SSc; and 2) To develop approaches for identification of the antigens recognized by these clonally-expanded gd TCR+ T-cells. Total RNA was isolated from the skin biopsies and peripheral blood of patients with SSc (n=8). After cDNA synthesis, the g- and d-chain TCR transcripts were amplified by PCR, cloned and sequenced for analysis. Full length copies of the TCR transcripts were constructed, expressed in a TCR-negative Jurkat T-cell line using retroviral gene transduction, and verified by RT-PCR and flow cytometry for gd TCR expression. Putative antigen recognition, by the transduced gd TCR+ Jurkat T-cell lines, was assessed via; 1) Measuring intracellular calcium flux in the transduced cells after stimulation with putative SSc antigens, including DNA topoisomerase I, centromere proteins A and B, hsp 27, hsp 90 and the viral lysate of human cytomegalovirus; and 2) Cytotoxicity against human endothelial cell lines (HUVEC and HLMVEC) via measurement of lactate dehydrogenase release from the targets. We report the presence of substantial, statistically-significant, proportions of identical g- and d-chain transcripts in skin biopsies and PBMC of patients with SSc, demonstrating the presence of antigen-driven clonal expansions. Jurkat T-cells, transduced with the clonally-expanded gd TCR transcripts from a patient, showed no evidence of cytotoxicity against the human endothelial cell lines, or calcium flux in response to stimulation with the putative SSc antigens assessed. In conclusion, extensive clonal expansions of g- and d-chain TCR transcripts were identified in skin biopsies and peripheral blood of patients with SSc, demonstrating the presence of oligoclonal populations of gd TCR+ T-cells in these patients. These gd TCR+ T-cells have undergone proliferation and clonal expansion in vivo in response to as yet unidentified antigens. Furthermore, an approach has been developed for the identification of the antigens recognized by the clonally-expanded gd TCR transcripts, which can be expanded to additional patients with SSc.