IMMUNOMODULATED SIGNALING IN MACROPHAGES - STUDIES ON ACTIVATION OF RAF-1, MAPK, CPLA(2) AND SECRETION OF IL-12

Little is known about the mechanism and signal transduction by LPS-med iated immunomodulation of murine peritoneal macrophages. It is found t hat the signal molecules of the down-stream of Ras, Raf-1, MAPK p44, a nd MAPK p42 are phosphorylated, and cPLA(2) is activated with a signif icant increase of the release of [H-3] AA by macrophages in response t o LPS and PMA. Compared with the very recent finding that LPS and PMA trigger the activation and translocation of PKC-alpha and PKC-epsilon, these findings suggest that there is a connection between PKC signali ng pathway and the Raf-1/MAPK pathway and that the activation of these main signaling events may he closely related to the secretion of IL-1 2 during LPS-induced modulation of macrophages.