Influence of anti-slime glycolipoprotein serum on the interaction between Pseudomonas aeruginosa and macrophages.

Glycolipoprotein, a purified fraction of the exopolysaccharide slime of Pseudomonas aeruginosa, was identified as responsible for a number of the biological activities of viable cells, including toxicity and immunogenicity capable of stimulating protective antibody against the lethal effects of viable cells. Antiserum against glycolipoprotein also mediated the phagocytosis and subsequent killing of viable P. aeruginosa by unstimulated mouse peritoneal macrophages. In the absence of anti-glycolipoprotein serum, macrophages did not significantly reduce the number of bacteria. The presence of complement in the experimental mixture did not affect the reduction of bacteria by the macrophage in the presence of anti-glycolipoprotein serum. The limiting effect of antiserum concentration on macrophage activity was studied, and maximal activity was found at 2%, with no further increase in activity at 5% Preopsonization of the bacteria with anti-glycolipoprotein serum had little effect on the course of phagocytosis within the experimental conditions. Variations in bacterium-to-macrophage input ratios, ranging from 30:1 to 1:30, did not affect the capacity of the macrophages for phagocytosis.