Immunological aspects of nitric oxide in HIV-1 infection.

Nitric oxide is produced in large amounts during host defense and immunological reactions and it is likely to have a role in non-specific immunity: nitric oxide exerts microbiostatic and microbicidal activity against a variety of pathogens, including protozoa, fungi, bacteria and some viruses. HIV-1 stimulates nitric oxide production by human macrophages and its production is increased in patients with HIV-1 infection. It is postulated that nitric oxide may play a part in modulating the immune response during HIV-1 infection. Nitric oxide produced by the HIV-1 infected monocytes/macrophages of lymph nodes, may adversely affect the survival of activated immune cells, including B and T lymphocytes and dendritic cells within their vicinity. It is suggested here that production of large amounts of nitric oxide by macrophages may lead to the inactivation of lymphocytes and thus to the induction of a persistent immunosuppression.