Long-term observation of baboons, rhesus monkeys, and chimpanzees inoculated with HIV and given periodic immunosuppressive treatment.

Baboons, rhesus monkeys, and chimpanzees were injected with the human immunodeficiency virus (HIV) and monitored for up to 4 years. Various immunosuppressive regimens were used during this time in attempts to induce development of the acquired immune deficiency syndrome (AIDS). No infectious virus was recovered or anti-HIV antibodies detected in the baboons and rhesus monkeys. Virus has been recovered from lymphocyte cultures of all five of the chimpanzees at intermittent periods following inoculation. The chimpanzees developed anti-HIV antibodies from 1 to 5 months after virus inoculation and had circulating antibodies that neutralized HIV. All the infected animals were capable of in vitro lymphocyte blastogenic responses to recombinant envelope and core HIV antigens. Despite immunosuppressive therapies and evidence of some immunologic abnormalities, none of the five chimpanzees has yet developed AIDS or a related disorder.