Removal of apoptotic cells and micro-organisms is mediated via phagocytosis. Phagocytes express pattern-recognition receptors (PRRs) that recognize apoptotic-cell-associated membrane patterns (ACAMPs). Similar ACAMPs and PRRs are used by mammals, Caenorhabditis elegans and Drosophila melanogaster. Some PRRs recognize apoptotic cells and micro-organisms, suggesting overlap between these functions.