Fig. 1.

Homeostatic clearance of apoptotic cells via different phagocytes. In many tissues of the body, clearance of apoptotic cells is performed by the professional phagocytes (P), which include the tissue resident macrophages and immature dendritic cells. Many non-hematopoietic cells also have phagocytic functions in ex vivo or in vitro systems. These non-professional phagocytes (NP) include epithelial cells, hepatocytes and endothelial cells of the liver¹¹, astrocytes, oligodendrocytes and neuronal progenitor cells of the central nervous system^108–111, or the Muller’s glia of the eye¹¹². Satellite cells of the skeletal muscle have also been reported to engulf apoptotic myoblasts³⁷. Specialized phagocytes (SP) are multifunctional cells that engulf apoptotic cells and include retinal pigment epithelial cell (RPE)¹¹³, and Sertoli cells in the testes¹⁶.