Interferon gamma priming is not critical for IL-12 production of murine spleen cells

Interferon gamma (IFN-gamma) priming is considered to be critical for inter leukin 12 (IL-12) production of murine macrophages and human monocytes by l ipopolysaccharide (LPS) stimulation. In our present experiments, freshly pr epared spleen cells (f-spleen cells) were confirmed not to produce detectab le level of IL-12 by LPS stimulation, although they produced Significant am ount of IL-12 by the stimulation with LPS plus IFN-gamma, However, the stim ulation only with LPS induced IL-12 production of spleen cells preincubated in the absence of IFN-gamma. Findings on IL-12 p40 mRNA accumulation were consistent with their IL-12 production. Essentially the same results were o btained using spleen cells from IFN-gamma deficient mice. In the presence o f anti-IL-10, f-spleen cells produced IL-12 upon LPS stimulation, indicatin g that the failure of f-spleen cells in IL-12 production is caused by IL-10 produced by themselves upon LPS stimulation. In addition, f-spleen cells p roduced IL-12 upon CD40 ligand stimulation, and the production was hardly a ffected by the presence of IFN-gamma or preincubation, These results indica te that IFN-gamma priming is not critical for IL-12 production of spleen ce lls stimulated with LPS or CD40 ligand, although IFN-gamma enhances the pro duction, especially, in response to LPS stimulation. (C) 2000 Academic Pres s.