Microglia progenitor cells: a subpopulation in cultures of mouse neopallial astroglia.

We have shown that astroglia cultures initiated from newborn mouse neopallium contain microglia progenitor cells. Astroglia secrete growth factor(s) that transform the progenitor cells into microglia. One of the trophic factors is bone marrow macrophage growth factor CSF-1. Mouse embryonic fibroblast cells STO also secrete trophic factor(s) that acts synergistically or additively with CSF-1 on microglia progenitor cells. Using limiting dilution analysis we estimated that in the presence of CSF-1 and STO cells, 1 in every 8 cells in astroglia cultures is a potential microglia progenitor cell.