Effects of a glycopolypeptide from the slime of P. aeruginosa on phagocytosis by mouse macrophages.

The isolation and characterization of a glycopolypeptide (GP) from the slime of Pseudomonas aeruginosa which has a marked effect on phagocytosis of P. aeruginosa cells by mouse macrophages is described. The GP was found to be a polysaccharide coupled with a polypeptide consisting of monomers with a molecular weight of 25,000. Immunization of mice with sublethal doses of the GP protected the animals against infection with the P. aeruginosa strain used for preparing the GP. Intraperitoneal administration of purified GP induced an increase in phagocytic activity of macrophages that was maximal after 13 days and specific for the strain of P. aeruginosa from which the GP was produced. The role of circulating antibody in enhancing phagocytic activity of peritoneal macrophages was discussed.