Microglia arise from CD45+ bone marrow precursors that colonize the fetal brain and play a key role in central nervous system inflammatory conditions. We report that parenchymal microglia are uncommitted myeloid progenitors of immature dendritic cells and macrophages by several criteria, including surface expression of "empty" class II MHC protein and their cysteine protease (cathepsin) profile. Microglia express receptors for stem cell factor and can be skewed toward more dendritic cell or macrophage-like profiles in response to the lineage growth factors granulocyte/ macrophage colony-stimulating factor or macrophage colonystimulating factor. Thus, in contrast to other organs, where terminally differentiated populations of resident dendritic cells and/ or macrophages outnumber colonizing precursors, the majority of microglia within the brain remain in an undifferentiated state.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - May 22 2001|
ASJC Scopus subject areas