Apoptotic cell removal

Ingestion by professional or amateur phagocytes is the fate of most cells t hat undergo apoptosis. Studies in both Caenorhabditis elegans and mammals a re now converging to reveal some of the key mechanisms and consequences of this removal process. At least seven corpse removal genes in nematodes have mammalian equivalents, and represent elements of signaling pathways involv ed in uptake. In mammals, a wide variety of apoptotic cell recognition rece ptors has been implicated and appears to be divided into two categories, in volved in tethering the apoptotic cell or triggering an uptake mechanism re lated to macropinocytosis. Apoptotic cell removal is normally efficient and non-inflammatory. By contrast, the process may become subverted by parasit es to yield a more favorable growth environment, or in other cases lead to fibrosis. Removal may also clinch the apoptotic process itself in cells not yet completely committed to death. (C) 2001 Elsevier Science Ltd. All righ ts reserved.