We investigated the hypothesis that exposure of monocytes to human immunodeficiency virus (HIV) augments production of proinflammatory mediators. The production of tumour necrosis factor alpha (TNF-alpha) and the eicosanoids PGE2 and LTB4 from human monocytes was evaluated after exposure to two strains of HIV (SSI-002 or HIV-1IIIB). After 16 h incubation with low doses of SSI-002, lipopolysaccharide-stimulated TNF-alpha production was enhanced 70-85% while PGE2 production was decreased. Heat-inactivated virus failed to alter the production of these mediators. Higher viral doses tended to decrease TNF-alpha and PGE2 production concomitantly, but this might be due to toxicity. HIV-1IIIB had no effect on either TNF-alpha or PGE2 production. Calcium ionophore-stimulated LTB4 production was doubled by HIV-1IIIB, but significantly decreased by SSI-002. Three or seven days after exposure to both HIV strains, increased PGE2 production was found. In conclusion, HIV only modestly altered the production of mediators from monocytes. The effects were strain-specific. In most experiments a second stimulus was required to demonstrate differences.