Repeated immunization with recombinant gp160 human immunodeficiency virus (HIV) envelope protein in early HIV-1 infection: Evaluation of the T cell proliferative response

This longitudinal study was designed to evaluate cellular immunity in early -stage, asymptomatic human immunodeficiency virus (HIV)-1-infected persons (CD4 cell count, >400/mm(3); median, 625/mm(3) who were immunized with eith er recombinant (r) gp160 or placebo every 2 months for 5 years. Proliferati ve responses were assessed against rgp160, rp24, and a panel of recall anti gens and mitogens. Despite good reactivity to recall antigens, at baseline similar to 33% had proliferative responses to gp160, and similar to 42% sho wed p24 gag responses. There was no statistical difference between vaccine and placebo groups for antigens or mitogens. After 1 year, similar to 73% o f the subjects in the vaccine arm had new or boosted responses to gp160, ve rsus similar to 18% in the placebo arm. Statistical significance was mainta ined throughout the study. Recurrent vaccination with recombinant gp160 was proven to be persistently immunogenic, increasing significantly the abilit y of HIV-1-infected persons to mount new proliferative responses to the vac cine.