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/mm3; median, 625/mm3) who were immunized with either recombinant (r) gp160 or placebo every 2 months for 5 years. Proliferative responses were assessed against rgp160, rp24, and a panel of recall antigens and mitogens. Despite good reactivity to recall antigens, at baseline ∼33% had proliferative responses to gp160, and ∼42% showed p24 gag responses. There was no statistical difference between vaccine and placebo groups for antigens or mitogens. After 1 year, ∼73% of the subjects in the vaccine arm had new or boosted responses to gp160, versus ∼18% in the placebo arm. Statistical significance was maintained throughout the study. Recurrent vaccination with recombinant gp160 was proven to be persistently immunogenic, increasing significantly the ability of HIV-1-infected persons to mount new proliferative responses to the vaccine.