Differential effects of Th1 and Th2 derived cytokines on NGF synthesis by mouse astrocytes

During the course of brain injury and inflammation there is an increased secretion of neurotrophic substances by astrocytes, We have examined the effect of the Th2-derived cytokine IL-10 and the Th1-derived cytokines IL-2 and IFN-gamma on the secretion of NGF by mouse astrocytes. IL-10 induced a dose-dependent increase in NGF secretion which was blocked by anti-IL-10 antibody, In contrast, the Th1-derived cytokines IFN-gamma and IL-2 did not induce NGF synthesis, Moreover, INF-gamma completely inhibited the increase in NGF secretion induced by IL-10 whereas it had no effect on the induction of NGF by TNF-alpha. These results indicate that IL-10 similarly to other Th2-derived cytokines may provide a neurotrophic support to injured neurons via the induction of NGF synthesis, whereas the Th1-derived cytokine IFN-gamma antagonizes this effect.