title: Identifying conserved DR1501-restricted CD4(+) T-cell epitopes in avian H5N1 hemagglutinin proteins.
abstract: Highly pathogenic avian influenza H5N1 viruses are capable of causing poultry epidemics and human mortality. Vaccines that induce protective neutralizing antibodies can prevent outbreaks and decrease the potential for influenza A pandemics. Identifying unique H5N1 virus-specific HLA class II-restricted epitopes is essential for monitoring cellular strain-specific immunity. Our results indicate that 80% of the 30 study participants who were inoculated with an H5N1 vaccine produced neutralizing antibodies. We used intracellular cytokine staining (ICS) to screen and identify six DR1501-restricted H5N1 virus epitopes: H5HA(148-162), H5HA(155-169), H5HA(253-267), H5HA(260-274), H5HA(267-281) and H5HA(309-323.) Tetramer staining results confirmed that two immunodominant epitopes were DR1501-restricted: H5HA(155-169) and H5HA(267-281). Both are located at the HA surface and are highly conserved in currently circulating H5N1 clades. These results suggest that a combination of ICS and tetramer staining can be used as a T-cell epitope-mapping platform, and the identified epitopes may serve as markers for monitoring vaccine efficacy.
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Sheng-Fan
authors.initials: SF
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Yao
authors.forename: Shih-Jen
authors.initials: SJ
authors.lastname: Liu
authors.forename: Pele
authors.initials: P
authors.lastname: Chong
authors.forename: Wu-Tse
authors.initials: WT
authors.lastname: Liu
authors.forename: Yi-Ming Arthur
authors.initials: YM
authors.lastname: Chen
authors.forename: Jason C
authors.initials: JC
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D057134:Antibodies, Neutralizing / Q000096:biosynthesis / Q000276:immunology; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000276:immunology; D018929:Cell Culture Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping / Q000379:methods*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008969:Molecular Sequence Data
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; C109963:hemagglutinin, avian influenza A virus