Influence on macrophage functions as a possible basis of immunomodification by polyanions

The effects of the polyanions, carrageenan, dextran sulphate, polyanetholesulphonate and suramin, on macrophage functions and on the complement system were studied. The function of phagosomes and lysosomes in vitro was inhibited by all polyanions but carrageenan whereas phagocytosis in vitro was enhanced by small doses of all polyanions. Interaction with complement occurred already at very low doses polyanion. On intraperitoneal administration, the polyanions inhibited the mononuclear phagocytic system as measured with the carbon clearance test. In some instances this was followed within 72 h by a stimulation. While polyanion injections caused an increase in spleen weight, the effects on the liver weight diverged. Our results and data of other authors suggest that the immunomodifying properties of the polyanions studied can be explained partly by drug-macrophage interaction, partly by indirectly mediated modulation of macrophage function.