Highly conserved cross-reactive CD4+ T-cell HA-epitopes of seasonal and the 2009 pandemic influenza viruses.

TitleHighly conserved cross-reactive CD4+ T-cell HA-epitopes of seasonal and the 2009 pandemic influenza viruses.
Publication TypeJournal Article
Year of Publication2010
AuthorsDuvvuri VRSK, Moghadas SM, Guo H, Duvvuri B, Heffernan JM, Fisman DN, Wu GE, Wu J
JournalInfluenza and other respiratory viruses
Date Published2010 Sep
KeywordsConserved Sequence, Cross Reactions, Epitopes, T-Lymphocyte, Hemagglutinins, Viral, Histocompatibility Antigens Class II, Humans, Immunity, Cellular, Influenza A Virus, H1N1 Subtype, Influenza A Virus, H3N2 Subtype, Influenza, Human

BACKGROUND: The relatively mild nature of the 2009 influenza pandemic (nH1N1) highlights the overriding importance of pre-existing immune memory. The absence of cross-reactive antibodies to nH1N1 in most individuals suggests that such attenuation may be attributed to pre-existing cellular immune responses to epitopes shared between nH1N1 virus and previously circulating strains of inter-pandemic influenza A viruses.

RESULTS: We sought to identify potential CD4+ T cell epitopes and predict the level of cross-reactivity of responding T cells. By performing large-scale major histocompatibility complex II analyses on Hemagglutinin (HA) proteins, we investigated the degree of T-cell cross-reactivity between seasonal influenza A (sH1N1, H3N2) from 1968 to 2009 and nH1N1 strains. Each epitope was examined against all the protein sequences that correspond to sH1N1, H3N2, and nH1N1. T-cell cross-reactivity was estimated to be 52%, and maximum conservancy was found between sH1N1 and nH1N1 with a significant correlation (P < 0.05).

CONCLUSIONS: Given the importance of cellular responses in kinetics of influenza infection in humans, our findings underscore the role of T-cell assays for understanding the inter-pandemic variability in severity and for planning treatment methods for emerging influenza viruses.

Alternate JournalInfluenza Other Respi Viruses