THE EFFECT OF PEPTIDE ANTIBIOTICS ON PHAGOCYTOSIS.

A phagocytosis-promoting factor (PPF) has been isolated from conventional and germfree guinea pig and rat peritoneal exudate fluid. The factor was found to resemble a globulin type of serum protein. It contained no hemolytic complement or gamma globulin. Electrophoresis under conditions of low pH and histochemical techniques indicated the PPF was a glycoprotein. Divalent cations were required for enhancement produced by the PPF. The terminal sialic acid group of the glycoprotein was shown to be indispensible for opsonic activity. The PPF appears to promote adsorption of bacteria to phagocyte but not ingestion. The PPF was inactive when used with polystyrene latex particles or with heterologous cells. (Author)