Passive immunization with human neutralizing monoclonal antibodies against HIV-1 in macaque models: experimental approaches.

After more than 20 years of intense research, a safe and effective vaccine against HIV-1/AIDS has not been developed. Passive immunization has been used as a tool to demonstrate the role of neutralizing antibodies in conferring protection against HIV-1 challenge in chimpanzees. Because these animals are endangered and studies are difficult to conduct with this species, chimeric viruses, termed simian-human immunodeficiency viruses (SHIVs), have been generated that encode the HIV-1 envelope gene in the backbone of the simian immunodeficiency virus (SIV). SHIVs replicate in several macaque species and can induce AIDS in these animals. Passive immunization with human neutralizing monoclonal antibodies (nmAbs) against HIV-1 has protected rhesus macaques from SHIV infection and provided proof-of-concept of the protective effects of neutralizing antibodies. At the same time, human nmAbs can be evaluated for safety and efficacy in the SHIV/macaque model as therapeutic modalities in their own right for prevention, post-exposure prophylaxis, or possibly therapeutic use. Experimental details are provided for testing human nmAbs in infant rhesus monkeys, which allows testing without the need to generate large amounts of nmAbs.