The Macrophage

The macrophage is one of the first cell types to be established in primary culture and has proved useful in the study of a great variety of problems in cell biology. Macrophages can be obtained from several mammalian species and birds. The mouse peritoneal macrophage offers special advantages as an experimental tool. Inbred and congenic mouse strains are a valuable source of genetically homogeneous and diploid cells. Pure populations of macrophages can be obtained by allowing peritoneal cell suspensions to attach to glass or plastic, followed by vigorous washing to remove nonadherent lymphoid cells. The macrophages can then be maintained, under defined conditions of cultivation, as a stable and uniform cell population, which undergoes no DNA synthesis or mitosis in vitro. Unlike many other cell types, the macrophage remains differentiated and continues to express cell-specific traits in culture, thus lending itself to studies on the control of cell growth and differentiation. In addition, the macrophage is particularly suited to the study of problems involving plasma membrane physiology and the vacuolar apparatus.