How do phagocytes eat?

Abstract

Phagocytosis is a cellular function relevant for host defense against infection, tissue turnover, and other aspects of human physiology. Phagocytosis is also representative of functions wherein external stimuli activate motile events in the cell. Recognition of suitable objects by the plasma membrane of the phagocyte initiates phagocytosis. Knowledge of serum proteins that coat objects rendering them recognizable is considerable, but understanding of the chemical basis of recognition is meager. The signals activated by recognition are also not known. The work of phagocytosis that causes pseudopodia to enclose objects in vacuoles is ascribable to metabolic energy-dependent interactions between actin filaments and other contractile proteins in the peripheral cytoplasm. These interactions may also regulate the fusion of lysosomes with phagocytic vacuoles, an event important for the processing of ingested objects after phagocytosis.