title: Prevention of HIV-1 IIIB infection in chimpanzees by CD4 immunoadhesin.
abstract: The first step in infection by the human immunodeficiency virus (HIV) is the specific binding of gp120, the envelope glycoprotein of HIV, to its cellular receptor, CD4. To inhibit this interaction, soluble CD4 analogues that compete for gp120 binding and block HIV infection in vitro have been developed. To determine whether these analogues can protect an uninfected individual from challenge with HIV, we used the chimpanzee model system of cell-free HIV infection. Chimpanzees are readily infected with the IIIB strain of HIV-1, becoming viraemic within about 4-6 weeks of challenge, although they do not develop the profound CD4+ T-cell depletion and immunodeficiency characteristic of HIV infection in humans. CD4 immunoadhesin (CD4-IgG), a chimaeric molecule consisting of the N-terminal two immunoglobulin-like regions of CD4 joined to the Fc region of human IgG1, was selected as the CD4 analogue for testing because it has a longer half-life than CD4, contributed by the IgG Fc portion of the molecule. In humans, this difference results in a 25-fold increased concentration of CD4-IgG in the blood compared with recombinant CD4. Here we report that pretreatment with CD4-IgG can prevent the infection of chimpanzees with HIV-1. The need for a preventative agent is particularly acute in perinatal HIV transmission. As recombinant CD4-IgG, like the parent IgG molecule, efficiently crosses the primate placenta, it may be possible to set up an immune state in a fetus before HIV transfer occurs, thus preventing infection.
authors.affiliation: Genentech Inc., S. San Francisco, California 94080.
authors.forename: R H
authors.initials: RH
authors.lastname: Ward
authors.forename: D J
authors.initials: DJ
authors.lastname: Capon
authors.forename: C M
authors.initials: CM
authors.lastname: Jett
authors.forename: K K
authors.initials: KK
authors.lastname: Murthy
authors.forename: J
authors.initials: J
authors.lastname: Mordenti
authors.forename: C
authors.initials: C
authors.lastname: Lucas
authors.forename: S W
authors.initials: SW
authors.lastname: Frie
authors.forename: A M
authors.initials: AM
authors.lastname: Prince
authors.forename: J D
authors.initials: JD
authors.lastname: Green
authors.forename: J W
authors.initials: JW
authors.lastname: Eichberg
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000517:prevention & control*; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000008:administration & dosage / Q000276:immunology* / Q000493:pharmacokinetics; D015703:Antigens, CD / Q000008:administration & dosage / Q000276:immunology* / Q000493:pharmacokinetics; D015704:CD4 Antigens / Q000276:immunology*; D016860:CD4 Immunoadhesins; D015497:HIV-1; D007116:Immunization, Passive; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G / Q000008:administration & dosage / Q000276:immunology* / Q000493:pharmacokinetics; D002679:Pan troglodytes; D011994:Recombinant Proteins
chemical_list: D000888:Antibodies, Anti-Idiotypic; D015703:Antigens, CD; D015704:CD4 Antigens; D016860:CD4 Immunoadhesins; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D011994:Recombinant Proteins