REGULATION OF MICROGLIAL FUNCTION BY INTERFERONS

Cultured neonatal rat microglia were pretreated with varying doses of either purified interferon (IFN) alpha/beta or recombinant IFN-gamma for 24 or 48 h and the following functional parameters examined; superoxide anion production, interleukin-1 secretion and chemotaxis. IFN-gamma produced a marked increase in superoxide anion levels when PMA was used to initiate superoxide anion production but had no effect in OPZ-stimulated microglia. Treatment with IFN-alpha/beta potentiated superoxide anion production in both PMA and OPZ-stimulated cells. Interleukin-I activity was decreased by treatment with IFN-gamma for 24 h while IFN-alpha/beta increased IL-1 activity at 48 h. Removal of serum from the treatment media prevented the action of IFN-alpha/beta on IL-1 production. Treatment with IFN-alpha/beta or gamma decreased chemotaxis of microglia in response to zymosan activated serum. The data indicate that IFN-gamma and alpha/beta can regulate microglial function and that this regulation may differ from that seen for other monocytically derived macrophages.