The disposal of dying cells in living tissues

Cells continuously die and disappear from the midst of living tissues. However, some of their constituents survive. DNA is horizontally transferred to phagocytic cells, and apoptotic cell antigens shape the immune repertoire. When massive apoptosis occurs, which overwhelms tissue scavenger cells, or when the function of phagocytes abates, dying cells escape clearance in vivo. Remnant dying cells come to phagocytes disguised: factors capable to envelop their membranes pervade the entire organism, or are generated in given tissues. Some are constitutively present, while other are generated during early or late phases of the inflammatory response, possibly to face the further burden of the dead inflammatory cells. This camouflage influences the disposal of the corpses: decoying molecules either bridge the corpse to the phagocyte or hide it. Furthermore, factors associated to the plasma membrane of the apoptotic cell shape the signals the phagocyte releases in situ. Finally, molecules contained or released by the dying cell alter the apprehension by the phagocyte of its prey, influencing its immunogenicity.