scholarly journals Cell lines transfected with the TAP inhibitor ICP47 allow testing peptide binding to a variety of HLA class I molecules [In Process Citation]

1998 ◽  
Vol 10 (11) ◽  
pp. 1665-1672 ◽  
Author(s):  
J Gatfield
Keyword(s):  
Cell Lines ◽  
Peptide Binding ◽  
Hla Class I ◽  
Class I ◽  
Hla Class I Molecules

scholarly journals The pockets guide to HLA class I molecules

2021 ◽  
Author(s):  
Andrea T. Nguyen ◽  
Christopher Szeto ◽  
Stephanie Gras
Keyword(s):  
T Cells ◽  
Cell Surface ◽  
Peptide Binding ◽  
Hla Class I ◽  
Class I ◽  
Side Chains ◽  
Binding Prediction ◽  
Peptide Residue ◽  
Hla Class I Molecules ◽  
Binding Pockets

Human leukocyte antigens (HLA) are cell-surface proteins that present peptides to T cells. These peptides are bound within the peptide binding cleft of HLA, and together as a complex, are recognised by T cells using their specialised T cell receptors. Within the cleft, the peptide residue side chains bind into distinct pockets. These pockets ultimately determine the specificity of peptide binding. As HLAs are the most polymorphic molecules in humans, amino acid variants in each binding pocket influences the peptide repertoire that can be presented on the cell surface. Here, we review each of the 6 HLA binding pockets of HLA class I (HLA-I) molecules. The binding specificity of pockets B and F are strong determinants of peptide binding and have been used to classify HLA into supertypes, a useful tool to predict peptide binding to a given HLA. Over the years, peptide binding prediction has also become more reliable by using binding affinity and mass spectrometry data. Crystal structures of peptide-bound HLA molecules provide a means to interrogate the interactions between binding pockets and peptide residue side chains. We find that most of the bound peptides from these structures conform to binding motifs determined from prediction software and examine outliers to learn how these HLAs are stabilised from a structural perspective.

844 Immunomodulatory activity of epigenetic drugs combinations in mesothelioma: laying the ground for new immunotherapeutic strategies

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A896-A896
Author(s):  
Sara Cannito ◽  
Health Biology ◽  
Ornella Cutaia ◽  
Carolina Fazio ◽  
Maria Fortunata Lofiego ◽  
...  
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Hla Class I ◽  
Class I ◽  
Immunomodulatory Activity ◽  
Epigenetic Drugs ◽  
Hla Class I Antigens ◽  
Hla Class I Molecules ◽  
Mesothelioma Cell Line ◽  
Mesothelioma Cell

BackgroundGrowing evidence are demonstrating the therapeutic efficacy of immune checkpoint inhibitors (ICI) in mesothelioma; however, a limited percentage of patients benefits from this therapeutic approach. Epigenetic modifications play a relevant role in negatively regulating the cross-talk between neoplastic and immune cells, and in contributing to the highly immunosuppressive mesothelioma microenvironment. A better understanding of mesothelioma epigenetic landscape could open the path to novel and potentially more effective approaches combining ICI and epigenetic drugs. We investigated the immunomodulatory potential of epigenetic agents by comparing the activity of DNA hypomethylating agents (DHA) with histone deacetylases inhibitors (HDACi) and EZH2 inhibitors (EZH2i), alone or combined with DHA, in mesothelioma cells.MethodsFour mesothelioma cell lines were treated with the DHA guadecitabine 1μM, or with the HDACi, Valproic Acid (VPA) 1mM, or the EZH2i, EPZ-6438 1μM, alone or combined with guadecitabine. We investigated the expression of HLA class I molecules by flow-cytometry and of PD-L1, cancer testis antigens (CTA: NY-ESO, MAGE-A1), Natural Killer Group 2 member D Ligands (NKG2DLs: MIC-A, MIC-B, ULBP2) and EMT-regulating cadherins (CDH1, CDH2) by quantitative Real-Time PCR. Fold change (FC) expression for each treatment vs untreated cells was reported as mean values (FCm) among investigated cell lines. A positive modulation of the expression was considered if FCm>1.5.ResultsGuadecitabine upregulated the expression of HLA class I antigens (FCm=1.75), PD-L1 (FCm=2.38), NKG2DLs (MIC-A FCm=1.96, MIC-B FCm=2.57, and ULBP2 FCm=3.56), and upregulated/induced CTA expression. Similarly, VPA upregulated HLA class I antigens (FCm=1.67), PD-L1 (FCm=3.17), NKG2DLs (MIC-A FCm=1.78, MIC-B FCm=3.04, and ULBP2 FCm=3.75) expression; however, CTA expression was modulated only in 1 mesothelioma cell line. Conversely, EPZ-6438 up-regulated only NY-ESO-1 and MIC-B expression in 1 mesothelioma cell line.The addition of both VPA and EPZ-6483 to guadecitabine strengthened its immunomodulatory activity. Specifically, guadecitabine plus VPA or EPZ-6438 upregulated the expression of HLA class I antigens FCm=2.55 or 2.69, PD-L1 FCm=8.04 or 2.65, MIC-A FCm=3.81 or 2.26, MIC-B FCm=8.00 or 3.03, ULBP2 FCm=6.24 or 4.53, respectively. Higher levels of CTA upregulation/induction were observed with combination treatments vs guadecitabine alone.Cadherins modulation was mesothelioma histotype-related: CDH1 expression was induced in the 2 constitutively-negative sarcomatoid mesothelioma cells by guadecitabine alone or combined with VPA or EPZ-6438; CDH2 expression was upregulated by VPA alone (FCm=1.53) or plus guadecitabine (FCm=2.54).ConclusionsCombination of DHA-based immunotherapies with other classes of epigenetic drugs could be an effective strategy to be pursued in the mesothelioma clinic.

scholarly journals HLA-derived peptides which inhibit T cell function bind to members of the heat-shock protein 70 family.

1996 ◽  
Vol 183 (2) ◽  
pp. 339-348 ◽  
Author(s):  
E Nossner ◽  
J E Goldberg ◽  
C Naftzger ◽  
S C Lyu ◽  
C Clayberger ◽  
...  
Keyword(s):  
T Cell ◽  
Heat Shock ◽  
T Lymphocytes ◽  
Heat Shock Protein ◽  
Cell Function ◽  
Peptide Binding ◽  
Hla Class I ◽  
Class I ◽  
Inhibitory Effects ◽  
Hla Class I Molecules

Synthetic peptides corresponding to sequences of HLA class I molecules have inhibitory effects on T cell function. The peptides investigated in this study have sequences corresponding to the relatively conserved region of the alpha 1 helix of HLA class I molecules that overlaps the "public epitope" Bw4/Bw6. These HLA-derived peptides exhibit inhibitory effects on T lymphocytes and have beneficial effects on the survival of allogenic organ transplants in mice and rats. Peptides corresponding to the Bw4a epitope appear most potent as they inhibit the differentiation of T cell precursors into mature cytotoxic T lymphocytes (CTL) and target cell lysis by established CTL lines and clones. To elucidate the mechanism through which these peptides mediate their inhibitory effect on T lymphocytes, peptide binding proteins were isolated from T cell lysates. We show that the inhibitory Bw4a peptide binds two members of the heat-shock protein (HSP) 70 family, constitutively expressed HSC70 and heat-inducible HSP70. Peptide binding to HSC/HSP70 is sequence specific and follows the rules defined by the HSC70 binding motif. Most intriguing, however, is the strict correlation of peptide binding to HSC/HSP70 and the functional effects such that only inhibitory peptides bind to HSC70 and HSP70 whereas noninhibitory peptides do not bind. This correlation suggests that small molecular weight HLA-derived peptides may modulate T cell responses by directly interacting with HSPs. In contrast to numerous reports of HSP70 expression at the surface of antigen-presenting cells and some tumor cells, we find no evidence that HSC/HSP70 are expressed at the surface of the affected T cells. Therefore, we believe that the peptides' immunodulatory effects are not mediated through a signaling event initiated by interaction of peptide with surface HSP, but favor a model similar to the action of other immunomodulatory compounds, FK506 and cyclosporin A, with a role for HSC/HSP70 similar to that for immunophilins, FKBPs and CyP40.

scholarly journals Amino acid substitution at peptide-binding pockets of HLA class I molecules increases risk of severe acute GVHD and mortality

Blood ◽  
2013 ◽  
Vol 122 (22) ◽  
pp. 3651-3658 ◽  
Author(s):  
Joseph Pidala ◽  
Tao Wang ◽  
Michael Haagenson ◽  
Stephen R. Spellman ◽  
Medhat Askar ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Peptide Binding ◽  
Hla Class I ◽  
Class I ◽  
Graft Versus Host ◽  
Hla Class I Molecules ◽  
Key Points ◽  
Binding Pockets ◽  
Binding Residues

Key Points Amino acid substitution at peptide-binding residues of the HLA class I molecule is associated with graft-versus-host disease and mortality. Avoidance of donor-recipient combinations that result in amino acid substitution at peptide-binding residues may improve transplant outcomes.

Multi-Drug Resistant Leukemic Cells Highly Express HLA Class I Molecules and Single-Chain Fv Diabody Specific to HLA-A Overcomes Drug Resistance in These Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2376-2376
Author(s):  
Ali Jalili ◽  
Shuji Ozaki ◽  
Naoki Kimura ◽  
Masahiro Abe ◽  
Toshio Matsumoto
Keyword(s):  
Tumor Cells ◽  
Cell Lines ◽  
Hla Class I ◽  
Resistant Cell ◽  
Class I ◽  
Single Chain ◽  
Expression Levels ◽  
Hla Class I Molecules ◽  
Single Chain Fv ◽  
Mdr 1

Abstract Many tumor cells become resistant to commonly used cytotoxic drugs due to the overexpression of ATP-binding cassette (ABC) transporters. Specifically, p-glycoprotein (MDR-1) is frequently up-regulated in chemotherapy-resistant tumor cells, which is associated with poor prognosis. On the other hand, human leukocyte antigen (HLA) class I molecules are known to be significantly down-regulated in advanced tumor cells to escape from immune surveillance. However, the relationship between MDR-1 expression and HLA expression is not fully understood. Recently, we have developed a recombinant single-chain Fv diabody specific to HLA-A and demonstrated that this agent mediates cell death in HLA-overexpressing lymphoid tumor cells but not in normal cells (Cancer Res2007; 67:1184). Here, we investigated the expression levels of HLA class I in chemo-resistant leukemic cells and evaluated the therapeutic potential of single-chain Fv diabody specific to HLA-A, C3B3-DB (Chugai Pharmaceutical Co. Ltd., Tokyo, Japan). Chemotherapy-resistant cells were established by subculturing of myeloid leukemia cell line HL60 and Burkitt’s lymphoma cell line BL-TH in increasing doses of vincristine (VCR), and named HL60/VCR and BL-TH/VCR, respectively. MDR-1 is strongly expressed in HL60/VCR and BL-TH/VCR cells both at the mRNA and protein levels, but not in the parental cells. Interestingly, expression levels of HLA class I molecules are 8 times higher in HL60/VCR and BL-TH/VCR cells than in the parental cells, suggesting that MDR-1 modulates cell surface expression of HLA by its transporter function. Next, we examined the cytotoxic activity of C3B3-DB on these chemo-resistant cell lines. C3B3-DB induced apoptosis in HL60/VCR and BL-TH/VCR cells and these chemo-resistant cell lines were more sensitive to C3B3-DB than the parent cells. Combination of C3B3-DB with chemotherapeutic agents such as VCR and daunorubicin (DNR) resulted in enhanced cytotoxicity against HL60/VCR and BL-TH/VCR cells. Importantly, pretreatment of these chemo-resistant cell lines with C3B3-DB reduced expression levels of MDR-1 and increased drug retention in these cells as detected by flow cytometry and confocal microscopy. Furthermore, combination of C3B3-DB with VCR significantly blocked the cell cycle at the G2 phase compared with VCR alone. Similar results were obtained with primary acute myeloid leukemia cells from 2 patients, resulting in up-regulation of both HLA class I and MDR-1 molecules at relapse phase compared at diagnosis. These results suggest that C3B3-DB enhances cytotoxicity of chemotherapeutic agents and provides a novel approach for overcoming drug resistance in hematological malignancies.

Downregulation of HLA Class I Molecules in Primary Oral Squamous Cell Carcinomas and Cell Lines

2009 ◽  
Vol 40 (4) ◽  
pp. 256-263 ◽  
Author(s):  
Qiusha Tang ◽  
Jianqiong Zhang ◽  
Bing Qi ◽  
Chuanlai Shen ◽  
Wei Xie
Keyword(s):  
Cell Lines ◽  
Squamous Cell ◽  
Hla Class I ◽  
Squamous Cell Carcinomas ◽  
Class I ◽  
Oral Squamous Cell Carcinomas ◽  
Hla Class I Molecules

scholarly journals HLA-E: A Novel Player for Histocompatibility

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Thomas Kraemer ◽  
Rainer Blasczyk ◽  
Christina Bade-Doeding
Keyword(s):  
Peptide Binding ◽  
Adaptive Immune System ◽  
Immunological Response ◽  
Human Leukocyte ◽  
Hla Class I ◽  
Cell Receptor ◽  
Class I ◽  
Structural Investigations ◽  
Immune Effector ◽  
Hla Class I Molecules

The classical class I human leukocyte antigens (HLA-A, -B, and -C) present allele-specific self- or pathogenic peptides originated by intracellular processing to CD8+immune effector cells. Even a single mismatch in the heavy chain (hc) of an HLA class I molecule can impact on the peptide binding profile. Since HLA class I molecules are highly polymorphic and most of their polymorphisms affect the peptide binding region (PBR), it becomes obvious that systematic HLA matching is crucial in determining the outcome of transplantation. The opposite holds true for the nonclassical HLA class I molecule HLA-E. HLA-E polymorphism is restricted to two functional versions and is thought to present a limited set of highly conserved peptides derived from class I leader sequences. However, HLA-E appears to be a ligand for the innate and adaptive immune system, where the immunological response to peptide-HLA-E complexes is dictated through the sequence of the bound peptide. Structural investigations clearly demonstrate how subtle amino acid differences impact the strength and response of the cognate CD94/NKG2 or T cell receptor.

The peptide binding specificity of HLA class I molecules is largely allele-specific and non-overlapping

1992 ◽  
Vol 29 (9) ◽  
pp. 1131-1140 ◽  
Author(s):  
Beatriz M. Carreno ◽  
Scott Koenig ◽  
John E. Coligan ◽  
William E. Biddison
Keyword(s):  
Peptide Binding ◽  
Hla Class I ◽  
Binding Specificity ◽  
Class I ◽  
Peptide Binding Specificity ◽  
Hla Class I Molecules ◽  
Allele Specific

scholarly journals Peptide Binding to HLA Class I Molecules: Homogenous, High-Throughput Screening, and Affinity Assays

2009 ◽  
Vol 14 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Mikkel Harndahl ◽  
Sune Justesen ◽  
Kasper Lamberth ◽  
Gustav Røder ◽  
Morten Nielsen ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Binding Assay ◽  
Peptide Binding ◽  
Hla Class I ◽  
Class I ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hla Class I Molecules ◽  
Hla Binding ◽  
Hla Molecules

The Human MHC Project aims at large-scale description of peptide-HLA binding to a wide range of HLA molecules covering all populations of the world and the accompanying generation of bioinformatics tools capable of predicting binding of any given peptide to any given HLA molecule. Here, the authors present a homogenous, proximity-based assay for detection of peptide binding to HLA class I molecules. It uses a conformation-dependent anti-HLA class I antibody, W6/32, as one tag and a biotinylated recombinant HLA class I molecule as the other tag, and a proximity-based signal is generated through the luminescent oxygen channeling immunoassay technology (abbreviated LOCI and commercialized as AlphaScreen™). Compared with an enzyme-linked immunosorbent assay—based peptide-HLA class I binding assay, the LOCI assay yields virtually identical affinity measurements, although having a broader dynamic range, better signal-to-background ratios, and a higher capacity. They also describe an efficient approach to screen peptides for binding to HLA molecules. For the occasional user, this will serve as a robust, simple peptide-HLA binding assay. For the more dedicated user, it can easily be performed in a high-throughput screening mode using standard liquid handling robotics and 384-well plates. We have successfully applied this assay to more than 60 different HLA molecules, leading to more than 2 million measurements. ( Journal of Biomolecular Screening 2009:173-180)

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