RESUMO
UNLABELLED: Cytotoxic T lymphocytes recognizing conserved peptide epitopes are crucial for protection against influenza A virus (IAV) infection. The CD8 T cell response against the M158-66 (GILGFVFTL) matrix protein epitope is immunodominant when restricted by HLA-A*02, a major histocompatibility complex (MHC) molecule expressed by approximately half of the human population. Here we report that the GILGFVFTL peptide is restricted by multiple HLA-C*08 alleles as well. We observed that M158-66 was able to elicit cytotoxic T lymphocyte (CTL) responses in both HLA-A*02- and HLA-C*08-positive individuals and that GILGFVFTL-specific CTLs in individuals expressing both restriction elements were distinct and not cross-reactive. The crystal structure of GILGFVFTL-HLA-C*08:01 was solved at 1.84 Å, and comparison with the known GILGFVFTL-HLA-A*02:01 structure revealed that the antigen bound both complexes in near-identical conformations, accommodated by binding pockets shaped from shared as well as unique residues. This discovery of degenerate peptide presentation by both HLA-A and HLA-C allelic variants eliciting unique CTL responses to IAV infection contributes fundamental knowledge with important implications for vaccine development strategies. IMPORTANCE: The presentation of influenza A virus peptides to elicit immunity is thought to be narrowly restricted, with a single peptide presented by a specific HLA molecule. In this study, we show that the same influenza A virus peptide can be more broadly presented by both HLA-A and HLA-C molecules. This discovery may help to explain the differences in immunity to influenza A virus between individuals and populations and may also aid in the design of vaccines.
Assuntos
Epitopos de Linfócito T/imunologia , Antígenos HLA-A/imunologia , Antígenos HLA-C/imunologia , Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Linfócitos T Citotóxicos/imunologia , Proteínas da Matriz Viral/imunologia , Sequência de Aminoácidos , Epitopos de Linfócito T/química , Epitopos de Linfócito T/genética , Antígenos HLA-A/química , Antígenos HLA-A/genética , Antígenos HLA-C/química , Antígenos HLA-C/genética , Humanos , Vírus da Influenza A/genética , Influenza Humana/genética , Influenza Humana/virologia , Interferon gama/imunologia , Dados de Sequência Molecular , Alinhamento de Sequência , Linfócitos T Citotóxicos/virologia , Proteínas da Matriz Viral/genéticaRESUMO
Bioorthogonal cleavable linkers are attractive building blocks for compounds that can be manipulated to study biological and cellular processes. Sodium dithionite sensitive azobenzene-containing (Abc) peptides were applied for the temporary stabilization of recombinant MHC complexes, which can then be employed to generate libraries of MHC tetramers after exchange with a novel epitope. This technology represents an important tool for high-throughput studies of disease-specific Tâ cell responses.