DIFFERENCES IN THE ANTIBODY-RESPONSE TO HUMAN IMMUNODEFICIENCY VIRUS-1 ENVELOPE GLYCOPROTEIN (GP160) IN INFECTED LABORATORY WORKERS AND VACCINEES

Studies of the immune response to the human immunodeficiency virus (HI V) have been hampered by the antigenic diversity of the HIV envelope p rotein. In an effort to predict the efficacy of vaccination we have co mpared the systemic anti-envelope antibody response in seronegative vo lunteers immunized with recombinant gp160 (either in vaccinia or as so luble protein produced in baculovirus) derived from the HTLV-IIIB stra in of HIV-1 and in two laboratory workers accidentally infected with t he same strain. 11 of 14 vaccinees responded to immunization by produc ing anti-gp160 of similar titer and the same isotype as that seen in t he laboratory workers. Four vaccinees also had antibody to the princip al neutralizing domain (V3 loop) that was comparable in titer with tha t seen in the laboratory workers, but the fine specificity of anti-V3 antibody was qualitatively different in the two groups. Antibody that can block the interaction between CD4 and gp120 was present at compara ble levels in three vaccinees and the lab workers. Neutralizing antibo dy titers were markedly lower in the vaccinees than in the laboratory workers. In seven of the vaccinees, an immunodominant epitope was at a mino acid 720-740. Analyses of monoclonal antibodies to this region in dicate that they do not neutralize, bind to infected cells, nor functi on as immunotoxins. Although the anti-gp160 antibody response was of s imilar magnitude in both infected and vaccinated individuals, there we re important qualitative differences.