Microglia can be considered the main cell in brain immune surveillance, can present antigens in the molecular context of MHC class II expression to CD-4 positive T cells, are capable of Fc-mediated phagocytosis, and share many common antigens with hemopoietic and tissue macrophages. Furthermore,microglia are involved in a variety of physiological and pathological processes in the brain by interacting with neurons and other glial cells and through production of biologically active substances such as growth factors, cytokines, and other factors.RM is isolated from day 2 rat brain tissue. Cells are harvested after purification and delivered frozen. Each vial contains >5 x 10^5 cells in 1 ml volume.