Molecular basis for universal HLA-A*0201-restricted CD8+ T-cell immunity against influenza viruses.

Proceedings of the National Academy of Sciences of the United States of America 2016 Apr 19

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Memory CD8(+)T lymphocytes (CTLs) specific for antigenic peptides derived from internal viral proteins confer broad protection against distinct strains of influenza A virus (IAV). However, immune efficacy can be undermined by the emergence of escape mutants. To determine how T-cell receptor (TCR) composition relates to IAV epitope variability, we used ex vivo peptide-HLA tetramer enrichment and single-cell multiplex analysis to compare TCRs targeted to the largely conserved HLA-A*0201-M158and the hypervariable HLA-B*3501-NP418antigens. The TCRαβs for HLA-B*3501-NP418 (+)CTLs varied among individuals and across IAV strains, indicating that a range of mutated peptides will prime different NP418-specific CTL sets. Conversely, a dominant public TRAV27/TRBV19(+)TCRαβ was selected in HLA-A*0201(+)donors responding to M158 This public TCR cross-recognized naturally occurring M158variants complexed with HLA-A*0201. Ternary structures showed that induced-fit molecular mimicry underpins TRAV27/TRBV19(+)TCR specificity for the WT and mutant M158peptides, suggesting the possibility of universal CTL immunity in HLA-A*0201(+)individuals. Combined with the high population frequency of HLA-A*0201, these data potentially explain the relative conservation of M158 Moreover, our results suggest that vaccination strategies aimed at generating broad protection should incorporate variant peptides to elicit cross-reactive responses against other specificities, especially those that may be relatively infrequent among IAV-primed memory CTLs.

Citation

Sophie A Valkenburg, Tracy M Josephs, E Bridie Clemens, Emma J Grant, Thi H O Nguyen, George C Wang, David A Price, Adrian Miller, Steven Y C Tong, Paul G Thomas, Peter C Doherty, Jamie Rossjohn, Stephanie Gras, Katherine Kedzierska. Molecular basis for universal HLA-A*0201-restricted CD8+ T-cell immunity against influenza viruses. Proceedings of the National Academy of Sciences of the United States of America. 2016 Apr 19;113(16):4440-5