IFN-alpha and IL-18 exert opposite regulatory effects on the IL-12 receptor expression and IL-12-induced IFN-gamma production in mouse macrophages: novel pathways in the regulation of the inflammatory response of macrophages
L. Fantuzzi et al., IFN-alpha and IL-18 exert opposite regulatory effects on the IL-12 receptor expression and IL-12-induced IFN-gamma production in mouse macrophages: novel pathways in the regulation of the inflammatory response of macrophages, J LEUK BIOL, 68(5), 2000, pp. 707-714
We characterized the IL-12 response of mouse macrophages in terms of mlodul
ation of IFN-gamma production by cytokines (IFN-alpha and IL-18) and regula
tion of IL-12 receptor expression, pi and beta2 IL-12R chain mRNA expressio
n increased with, time in culture in the absence of exogenous stimulation,
with concomitant acquisition of responsiveness to IL-12 for IFN-gamma produ
ction. Expression of the IL-12R beta1 chain mRNA was increased further foll
owing IL-12 treatment as a consequence of IFN-gamma expression, IL-12 respo
nse was regulated differentially by IFN-alpha and IL-18, Neutralization of
endogenous type I IFN increased IFN-gamma secretion, whereas exogenous IFN-
alpha reduced it. In contrast, IL-18 enhanced IFN-gamma mRNA accumulation a
nti. IFN-gamma secretion in IL-12-stimulated, hut not -untreated, cultures.
The opposite effects exerted by IFN-alpha and IL-18 mirror their mutual ca
pacity of regulating-in a negative or positive manner, respectively-the exp
ression of the IL-12R beta1 drain. We suggest that differential regulation
of IL-12 response by IFN-alpha and IL-18 can represent previously unrecogni
zed regulatory mechanisms for maintaining suitable levels of differentiatio
n/activation in macrophages.