title: Simple enzyme immunoassay for titration of antibodies to the CD4-binding site of human immunodeficiency virus type 1 gp120.
abstract: We report the development of an immunoassay for the titration of antibody to the CD4-binding site (CD4BS) of the human immunodeficiency virus type 1 (HIV-1) surface glycoprotein gp120. This assay is a competitive enzyme-linked immunosorbent assay in which serum antibodies compete with labeled F105, a human monoclonal antibody whose corresponding epitope overlaps the conformation-dependent CD4BS, for binding to purified recombinant gp120 coated on a solid phase. Ninety-nine percent (109 of 110) of HIV-1-positive French patients and 91% (51 of 56) of HIV-1-positive African patients had CD4BS antibodies, indicating that the conformational CD4BS epitope is well conserved among different subtypes of HIV-1. Titers of CD4BS antibodies according to clinical status appeared to be not statistically different. A longitudinal study in 21 seroconverters showed that, for the majority of individuals, CD4BS antibodies appeared early and persisted at relatively high titers for several years. None of 21 HIV-2-seropositive patients had CD4BS antibodies in our assay, suggesting that the antibodies produced during HIV-2 infection are not cross-reactive with the CD4BS of HIV-1 gp120.
authors.affiliation: Département de Microbiologie Médicale et Moléculaire, Unité de Recherche Associée Centre National de la Recherche Scientifique 1334, Centre Hospitalier Universitaire Bretonneau, Tours, France.
authors.forename: I
authors.initials: I
authors.lastname: Turbica
authors.forename: M
authors.initials: M
authors.lastname: Posner
authors.forename: C
authors.initials: C
authors.lastname: Bruck
authors.forename: F
authors.initials: F
authors.lastname: Barin
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D015704:CD4 Antigens / Q000378:metabolism*; D016384:Consensus Sequence; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015483:HIV Antibodies / Q000032:analysis*; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015658:HIV Infections / Q000276:immunology; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D015498:HIV-2 / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
chemical_list: D015704:CD4 Antigens; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120