Human polymorphonuclear leukocytes (PMN) stimulated by lipopolysaccharide (LPS) produce interleukin-12 (IL-12). Both the free IL-12 p40 chain and minute amounts of the biologically active IL-12 p70 heterodimers are produced by PMN. Interferon-gamma (IFN-gamma) enhanced the LPS-induced secretion of both the free IL-12 p40 chain and the p70 heterodimer by approximately fivefold. As observed for other IL-12-producing cell types, the ratio of free p40 chain to p70 heterodimer secreted by LPS-stimulated PMN was approximately 20:1. LPS induced a 100-fold increase of IL-12 p40 mRNA, but had minimal effect on p35 mRNA accumulation. IFN-gamma enhanced the LPS-induced accumulation of p40 mRNA and directly induced a several-fold increase in the accumulation of p35 mRNA. Therefore, the combined effect of LPS and IFN-gamma induced sufficient expression of both p40 and p35 to attain production of the biologically active p70 heterodimer at physiologically relevant concentrations. The ratio between p40 and p35 mRNA abund
File in questo prodotto:
Non ci sono file associati a questo prodotto.