Preterm labor is associated with increased intrauterine prostaglandin (PG) production. Intrauterine infections are frequently associated with preterm labor and increased cytokine production. The cytokine interleukin-2 (IL-2) is a potent T-cell growth factor necessary for effective cell-mediated immunity. In this study we evaluated the effects of IL-2 on PGE2 biosynthesis by human amnion cells. IL-2 alone modestly but significantly inhibited amnion PGE2 production. Moreover, IL-2 also attenuated, in a concentration-related fashion, the stimulatory actions of IL-1 beta on PGE2 production by amnion cells. These data suggest that IL-2 could potentially represent a negative regulatory element in the mechanisms of preterm labor in association with intrauterine infection.