The immunobiology of human Fcγ receptors on hematopoietic cells and tissue macrophages

The ability to identify and remove potentially dangerous foreign organisms and proteins is critical to the survival of a species. In humans, IgG antibodies serve to recognize such foreign antigens and to facilitate their removal. The latter process involves several hematopoietic cells, including those of the macrophage phagocytic system, which express Fcγ receptors. These receptors specifically recognize the Fc domain of IgG antibody. On the surface of hematopoietic cells these Fcγ receptors mediate cell attachment and stimulate several signal transduction events, including those which lead to phagocytosis. Moreover, their perturbation can lead to the generation and release of mediators and enzymes involved in inflammation and in the pathogenesis of autoimmune diseases.