Immunophenotypic characterization of rat brain macrophages in culture

Five monoclonal antibodies specific for rat monocytes/macrophages were used to characterize macrophages/microglia bulk isolated from neonatal and adult rat brain. The majority of brain macrophages was positive for all antibodies tested with minor differences between cultures derived from developing and mature central nervous tissue. These results contrast in vivo findings indicating that most antigens of peripheral macrophages are absent from resting, activated and phagocytic microglia in situ. We conclude that brain macrophages/microglia newly express antigens of the myelomonocytic lineage when in culture and that cultured brain macrophages may be derived from different types of precursor cells normally present within the CNS.