Local proliferation of brain macrophages in central nervous system tissue cultures.

Mouse central nervous system tissue cultured for different lengths of time was analyzed for the proliferation of macrophages. These cells were identified and characterized by ultrastructural features, cell surface determinants and their ability to ingest latex particles and bacteria. Under the experimental conditions chosen brain macrophages were derived from perivascular cells which in short term cultures remained attached to blood vessels and later differentiated into brain macrophages with a typical ultrastructural appearance. Identical results were obtained when intravascular cells were largely removed by extensive saline perfusion before culturing. Macrophages assembled around stab wounds of the central nervous system or obtained from peritoneal lavage showed comparable cytological characteristics and cell membrane determinants.