Abstract
Attachment of bacteria to phagocytic cells is augmented by opsonins due to Fc and C3 receptors. It has also been shown, that intracellular killing even of C-resistant bacteria is increased following opsonization by C, but not by IgG. The mechanism of this C activity is yet unknown. C activation could lead either to an increased ingestion or increased discharge of lysosomal enzymes into the phagosome. The contribution of C activation to ingestion, killing and destruction of E. coli and to the secretion of lysosomal enzymes into the phagosome was therefore the subject of this investigation.
To a monolayer of human PMN radiolabelled E. coli were added following opsonization with IgG, C or IgG and C. After various time intervals, cells and nonattached bacteria were separated, cells were destroyed and the cell sap was separated by centrifugation into three fractions: 1) membrane (and nuclei), 2) granula, and 3) cytoplasma.
