title: Vaccine-induced CD4+ T cells against the simian immunodeficiency virus gag protein. Epitope specificity and relevance to protective immunity.
abstract: We have examined the induction and epitope specificity of T cells for the simian immunodeficiency virus (SIV) gag p27 protein in macaques immunized with either a recombinant SIV gag protein or an inactivated SIV vaccine. CD4+ MHC class II-restricted T cell lines and clones derived from five immunized macaques recognized a total of seven peptides in three immunodominant regions of p27. Two T cell clones generated from one of the lines, recognized a single 20 amino acid peptide that overlapped with a region previously shown to include a CTL epitope from SIV-infected macaques. Although this epitope is in a conserved region of the gag protein of SIV, its recognition by a CD4+ T cell clone was abrogated by sequence variation in the equivalent HIV protein. The specificity of the T cell lines for synthetic peptides demonstrated considerable overlap between T cells generated by immunization with the recombinant gag protein and inactivated SIV. However, in contrast to the protective efficacy of the whole virus vaccine in the syntex adjuvant formulation, immunization with the p27 protein with alum failed to generate a protective immune response. Furthermore, despite the consistent gag-specific T cell responses induced by the recombinant protein, there was no evidence of an enhanced antibody response to envelope (env) after live SIV challenge.
authors.affiliation: National Institute for Biological Standards and Control, Potters Bar, Herts, UK.
authors.forename: K H
authors.initials: KH
authors.lastname: Mills
authors.forename: A L
authors.initials: AL
authors.lastname: Barnard
authors.forename: M
authors.initials: M
authors.lastname: Williams
authors.forename: M
authors.initials: M
authors.lastname: Page
authors.forename: C
authors.initials: C
authors.lastname: Ling
authors.forename: E J
authors.initials: EJ
authors.lastname: Stott
authors.forename: P
authors.initials: P
authors.lastname: Silvera
authors.forename: F
authors.initials: F
authors.lastname: Taffs
authors.forename: A S
authors.initials: AS
authors.lastname: Kingsman
authors.forename: S E
authors.initials: SE
authors.lastname: Adams
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D000939:Epitopes; D015686:Gene Products, env / Q000276:immunology; D015683:Gene Products, gag / Q000276:immunology*; D008213:Lymphocyte Activation; D008252:Macaca fascicularis; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000939:Epitopes; D015686:Gene Products, env; D015683:Gene Products, gag; D010455:Peptides; D014614:Vaccines, Synthetic; D014765:Viral Vaccines