title: Searching immunodominant epitopes prior to epidemic: HLA class II-restricted SARS-CoV spike protein epitopes in unexposed individuals.
abstract: Identification of dominant T cell epitopes within newly emerging and re-emerging infectious organisms is valuable in understanding pathogenic immune responses and potential vaccine designs. However, difficulties in obtaining samples from patients or convalescent subjects have hampered research in this direction. We demonstrated a strategy, tetramer-guided epitope mapping, that specific CD4+ T cell epitopes can be identified by using PBMC from subjects that have not been exposed to the infectious organism. Sixteen HLA-DR0401- and 14 HLA-DR0701-restricted epitopes within spike protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) were identified. Among these, spike protein residues 159-171, 166-178, 449-461 and 1083-1097 were identified to contain naturally processed immunodominant epitopes based on strong in vitro T cell responses of PBMC (as assayed by tetramer staining) to intact spike protein stimulation. These immunodominant epitopes were confirmed in vivo in HLA-DR0401 transgenic mice by immunizing with spike protein. Furthermore, the epitope-specific T cells from naive donors secreted IFN-gamma and IL-13 upon re-stimulation with corresponding tetramers. Our study demonstrates a strategy to determine potential immunodominant epitopes for emerging infectious pathogens prior to their epidemic circulation.
authors.affiliation: Benaroya Research Institute at Virginia Mason, Seattle, WA, USA.
authors.forename: Junbao
authors.initials: J
authors.lastname: Yang
authors.forename: Eddie
authors.initials: E
authors.lastname: James
authors.forename: Michelle
authors.initials: M
authors.lastname: Roti
authors.forename: Laurie
authors.initials: L
authors.lastname: Huston
authors.forename: John A
authors.initials: JA
authors.lastname: Gebe
authors.forename: William W
authors.initials: WW
authors.lastname: Kwok
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D018604:Epitope Mapping; D000949:Histocompatibility Antigens Class II / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology* / Q000378:metabolism; D045169:Severe Acute Respiratory Syndrome / Q000453:epidemiology / Q000276:immunology* / Q000821:virology; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000276:immunology* / Q000378:metabolism
chemical_list: D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D016056:Immunodominant Epitopes; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins