title: Selective pressure exerted by immunodominant HIV-1-specific cytotoxic T lymphocyte responses during primary infection drives genetic variation restricted to the cognate epitope.
abstract: HIV-specific cytotoxic T lymphocytes (CTL) play a central role in the control of HIV-1 replication during primary infection. It has been hypothesized that the appearance of CTL escape mutants represents an important mechanism by which HIV-1 escapes the host cell-mediated immune response. However, evidences for a direct relationship between CTL responses and emergence of CTL escape mutants are still limited. Here we report detailed longitudinal analysis of DNA sequence variation performed over the entire HIV-1 envelope in two subjects during primary HIV infection. Estimates of the frequencies of synonymous (ds) and non-synonymous (dN) nucleotide substitutions were used to identify regions of the HIV-1 envelope which were subjected to significant levels of selective pressure. These regions were shown to comprise defined epitopes recognized by CTL. Furthermore, dN mutation fixed within these epitopes effectively abolished recognition by the host CTL response. These results provide compelling evidence that the CTL epitope mutations directly resulted from the selective pressure exerted by the virus-specific cytotoxic response.
authors.affiliation: Laboratory of AIDS Immunopathogenesis, Department of Internal Medicine,Centre hospitalier universitaire vaudois, Lausanne, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Soudeyns
authors.forename: S
authors.initials: S
authors.lastname: Paolucci
authors.forename: C
authors.initials: C
authors.lastname: Chappey
authors.forename: M B
authors.initials: MB
authors.lastname: Daucher
authors.forename: C
authors.initials: C
authors.lastname: Graziosi
authors.forename: M
authors.initials: M
authors.lastname: Vaccarezza
authors.forename: O J
authors.initials: OJ
authors.lastname: Cohen
authors.forename: A S
authors.initials: AS
authors.lastname: Fauci
authors.forename: G
authors.initials: G
authors.lastname: Pantaleo
mesh_terms: D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000235:genetics* / Q000276:immunology; D014644:Genetic Variation; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000235:genetics / Q000276:immunology; D015658:HIV Infections / Q000097:blood / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology*; D011446:Prospective Studies; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D016056:Immunodominant Epitopes