title: HIV-1 envelope-elicited neutralizing antibody titres correlate with protection and virus load in chimpanzees.
abstract: In an attempt to compare the protective effect of vaccination with two forms of envelope antigens, and to define immunological correlates of protection against HIV infection, chimpanzees were vaccinated with either recombinant gp160 or gp120. Homologous HIV challenge was performed 3 weeks after the fourth immunization. The animal with the highest level of serum neutralizing antibodies (gp160 immunogen) was protected against HIV infection. All other chimpanzees became infected, but displayed various levels of infected PBMCs. The postchallenge data gave rise to the following conclusions: (1) protection correlated with the level of the serological immune response, but not with the nature of immunogen (gp120 versus gp160); (2) the virus-neutralizing titre at day of challenge correlated with protection from infection; (3) the relative magnitude of the lymphoproliferative T-cell response at day of challenge did not correlate with any protective effect; (4) the peak numbers of virus-infected PBMCs in vaccinated animals were lower than those observed in control animals, and this effect was correlated with the intensity of the antibody response at day of challenge. This raises the possibility that a beneficial effect of HIV vaccination may be achieved in a situation where sterile immunity is not consistently obtained.
authors.affiliation: SmithKline Beecham Biologicals, Rixensart, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Bruck
authors.forename: C
authors.initials: C
authors.lastname: Thiriart
authors.forename: L
authors.initials: L
authors.lastname: Fabry
authors.forename: M
authors.initials: M
authors.lastname: Francotte
authors.forename: P
authors.initials: P
authors.lastname: Pala
authors.forename: O
authors.initials: O
authors.lastname: Van Opstal
authors.forename: J
authors.initials: J
authors.lastname: Culp
authors.forename: M
authors.initials: M
authors.lastname: Rosenberg
authors.forename: M
authors.initials: M
authors.lastname: De Wilde
authors.forename: P
authors.initials: P
authors.lastname: Heidt
authors.forename: J
authors.initials: J
authors.lastname: Heeney
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D015686:Gene Products, env / Q000276:immunology* / Q000627:therapeutic use; D015752:Genes, env / Q000235:genetics; D015483:HIV Antibodies / Q000096:biosynthesis*; D015699:HIV Envelope Protein gp120 / Q000276:immunology* / Q000627:therapeutic use; D019302:HIV Envelope Protein gp160; D015658:HIV Infections / Q000276:immunology / Q000517:prevention & control; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D007111:Immunity, Cellular; D007117:Immunization, Secondary; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests; D009504:Neutrophils / Q000166:cytology / Q000276:immunology; D002679:Pan troglodytes; D011498:Protein Precursors / Q000276:immunology* / Q000627:therapeutic use; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D016915:AIDS Vaccines; D015686:Gene Products, env; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D011498:Protein Precursors; D014614:Vaccines, Synthetic