Cytotoxic T cell recognition of allelic variants of HLA B35 bound to an Epstein-Barr virus epitope: influence of peptide conformation and TCR-peptide interaction

Abstract

Fine specificity analysis of HLA B35-restricted Epstein-Barr virus (EBV)-specific cytotoxic T lymphocyte (CTL) clones revealed a unique heterogeneity whereby one group of these clones cross-recognized an EBV epitope (YPLHEQHGM) on virus-infected cells expressing either HLA B*3501 or HLA B*3503, while another group cross-recognized this epitope in association with either HLA B*3502 or HLA B*3503. Peptide binding and titration studies ruled out the possibility that these differences were due to variation in the efficiency of peptide presentation by the HLA B35 alleles. Sequence analysis of the TCR genetic elements showed that these clonotypes either expressed BV12/AV3 or BV14/ADV17S1 heterodimers. Interestingly, CTL analysis with monosubstituted alanine mutants of the YPLHEQHGM epitope indicated that the BV12/AV3+ clones preferentially recognized residues towards the C terminus of the peptide, while the BV14/ADV17S1+ clones interacted with residues towards N terminus of the peptide. Molecular modelling of the MHC-peptide complexes suggests that the differences in two floor positions (114 and 116) of the HLA B35 alleles dictate different conformations of the peptide residues L3 and/or H7 and directly contribute in the discerning allele-specific immune recognition by the CTL clonotypes. These results provide evidence for a critical role for the selective interaction of the TCR with specific residues within the peptide epitope in the fine specificity of CTL recognition of allelic variants of an HLA molecule.

Ex Vivo Profiling of CD8+-T-Cell Responses to Human Cytomegalovirus Reveals Broad and Multispecific Reactivities in Healthy Virus Carriers

“…T2 cells expressing HLA B35, B7, and B27 have been described elsewhere (44,46,53). T2 cells expressing HLA A3, A24, and B8 were established by transfecting expression vectors encoding individual class I alleles as described previously (24). Briefly, cDNA for these HLA class I alleles was amplified using sequence-specific primers and cloned into an EGFP-N1 expression vector, which contains a green fluorescent protein tag and an antibiotic resistance gene to allow for positive selection.…”

High Resolution Structures of Highly Bulged Viral Epitopes Bound to Major Histocompatibility Complex Class I

“…The mutant lymphoblastoid cell line ϫ T lymphoblastoid hybrid cell line 174xCEM.T2 (referred to as T2 cells) (34), expressing HLA-B*3508 (T2.B*3508) (27,35), was also used in this study. Phytohemagglutinin (PHA) blasts were generated by stimulating peripheral blood mononuclear cells (PBMCs) with PHA (Sigma), and after 3 days, growth medium containing supernatant from the interleukin-2-producing cell line MLA-144 (European Collection of Cell Cultures) and recombinant interleukin-2 (rIL-2) were added.…”

RelB Nuclear Translocation Mediated by C-Terminal Activator Regions of Epstein-Barr Virus-Encoded Latent Membrane Protein 1 and Its Effect on Antigen-Presenting Function in B Cells

“…The EBV-specific CTL clones used in this study were LC13 (EBNA3 specific, HLA B8 restricted), NB37 (EBNA3 specific, HLA B35 restricted), and NB26 (EBNA3 specific, HLA B35 restricted). The specificity of these clones has been defined at the peptide epitope level: LC13 recognizes the minimal epitope sequence FLRGRAYGL (3), while NB37 and NB26 recognize the minimal epitope sequence YPLHEQHGM (2,24). These clones were maintained in growth medium containing highly purified recombinant human interleukin-2 from Escherichia coli.…”