Prevention of HIV-1 infection in chimpanzees by gpl20 V3 domain-specific monoclonal antibody

THE acquired immunodeficiency syndrome (AIDS) is the late-stage clinical manifestation of long-term persistent infection with the human immunodeficiency virus type 1 (HIV-1). Immune responses directed against the virus and against virus-infected cells during the persistent infection fail to mediate resolution of the infection. As a result, a successful AIDS vaccine must elicit an immune state that will prevent the establishment of the persistent infection following introduction of the virus into the host. The third hyper-variable (V3) domain of the HIV-1 gp120 envelope glycoprotein is a disulphide-linked closed loop of about 30 amino acids which binds and elicits anti-HIV-1 type-specific virus-neutralizing antibodies^1-7. The in vitro characteristics of anti-V3 domain antibody suggest that this antibody could by itself prevent HIV-1 infection in vivo^8,9, an idea supported by chimpanzee challenge studies in which protection against the HIV-1 persistent infection seemed to correlate with the presence of anti-V3 domain antibody^10-12. Here we directly demonstrate the protective efficacy of anti-V3 domain antibody in vivo and propose that this antibody is potentially useful as both a pre- and post-exposure prophylactic agent.