Prospects for the prevention and therapy of infections with the human immunodeficiency virus.

The current epidemic of acquired immunodeficiency syndrome (AIDS) poses a major threat to our population. Urgently needed are both a vaccine to prevent infection with the etiologic retrovirus, human immunodeficiency virus (HIV), and safe, effective antiviral agents to treat those individuals already infected. The elucidation of viral replicative mechanisms has allowed the development and testing of several agents active against HIV in vitro. Inhibitors of reverse transcriptase that have demonstrated activity include azidothymidine, phosphonoformate, antimoniotungstate (HPA-23), and suramin. Ribavirin and recombinant interferon alpha-A (IFN-alpha-A) also inhibit HIV replication, although their mechanisms of action are less clear. All of these compounds are undergoing early clinical trials in patients with HIV infection. The identification of immunogenic viral proteins may allow the development of one or more subunit vaccines against HIV. Studies are underway to clone appropriate viral genes and incorporate the expressed proteins into vectors for administration. Laboratory models, e.g., chimpanzees, will be inoculated with candidate vaccines and, if successful, this will be followed by clinical trials for safety and efficacy in appropriate human populations seronegative for HIV. Although important problems, such as virus envelope protein variability, need to be addressed, efforts to develop effective vaccines may well prove successful in the years ahead.