title: H5N1 strain-specific hemagglutinin CD4+ T cell epitopes restricted by HLA DR4.
abstract: CD4+ T cells play a pivotal role in the viral immunity, and as such identification of unique strain-specific HLA class II restricted epitopes is essential for monitoring cellular strain-specific viral immunity. Using Tetramer-Guided Epitope Mapping technique, we identified HLA-DR0401 restricted HA epitopes that are strain-specific to H5N1 virion. Two immunodominant epitopes H5HA(441-460) and H5HA(57-76) were identified from in vitro stimulated human PBMC. Both epitopes elicit strong cellular immune responses when HLA-DR0401 transgenic mice are immunized with H5N1 subvirion indicating in vivo naturally processed immunodominant epitopes. The H5HA(57-76) epitope is unique for the H5N1 strain but conserved among all H5N1 clades recommended for vaccine development by World Health Organization. The unique H5HA(57-76) response was uncommon in unexposed individuals and only observed in the naïve T cell subset. Thus, H5N1 strain-specific H5HA(57-76) immunogenic epitope represents a unique marker for monitoring the efficacy of vaccination or as a candidate vaccine peptide.
authors.affiliation: Benaroya Research Institute at Virginia Mason, Seattle, WA 98101-2795, United States.
authors.forename: Junbao
authors.initials: J
authors.lastname: Yang
authors.forename: John A
authors.initials: JA
authors.lastname: Gebe
authors.forename: Laurie
authors.initials: L
authors.lastname: Huston
authors.forename: Eddie
authors.initials: E
authors.lastname: James
authors.forename: Venus
authors.initials: V
authors.lastname: Tan
authors.forename: Betty B
authors.initials: BB
authors.lastname: Yue
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Nepom
authors.forename: William W
authors.initials: WW
authors.lastname: Kwok
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D015804:HLA-DR4 Antigen / Q000276:immunology*; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D018984:Epitopes, T-Lymphocyte; D015804:HLA-DR4 Antigen; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C109963:hemagglutinin, avian influenza A virus