Neopterin production by HIV-i-infected mononuclear ph agocytes

Abstract: Neopterin ms a pteridine produced by human mononuclear phagocytes, usually in response to interfemn--y (IFN-y) stimulation. Increasing serum levels of neopterin correlate with clinical progression to AIDS mn HIV-infected people, but the factors that contribute to these elevated levels are not established. We performed in vitro experiments to investigate the possibility that HIV-1 in-fection of mononuclear phagocytes directly induces en-hanced neopterin production. We found that HIV-1-in-fected monocytes and peritoneal macrophages produced neopterin in quantities similar to amounts produced by uninfected cells. The HIV-infected cells responded to stimulation with IFN-y as well as uninfected cells, with a 6- to 12-fold increase in neopterin production. We con-clude that elevated serum levels of neopterin in HIV-infected individuals are not caused by HIV-1 infection of mononuclear phagocytes but may be a result of the nor-mal response of mononuclear phagocytes to increased levels of IFN-’y. J. Leukoc. Biol. 56: 650-653; 1994. Key Words: monocytes macrophages. AIDS ’ interferon-