Influence of interleukin-1 and tumor necrosis factor alpha on the growth of microglial cells in primary cultures of mouse cerebral cortex: involvement of colony-stimulating factor 1.

The influence of monokines and CNS-derived colony-stimulating factors (CSF) on the growth of microglia has been studied in mixed glial primary cultures stemming from mouse embryos. We observed that spontaneous growth of microglial cells in the presence of astrocytes is blocked by adding anti-colony-stimulating factor 1 (CSF-1) antibodies to the cultures. Both interleukin-1 (IL-1) and tumor necrosis factor-alpha(TNF alpha) strongly increased the number of microglial cells in mixed glial cultures and this effect was prevented by anti-CSF-1 antibodies. In contrast, anti-interleukin-3 (IL-3) or anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies did not significantly affect the in vitro growth of microglia. These results provide functional significance to astrocytic productions of CSF-1 and their modulations by IL-1 or TNF alpha.