Isolation and chemical characterization of a granuloma glycoprotein that inhibits macrophage phagocytosis.

A saline soluble glycoprotein isolated from 14- and 42-day polyvinyl sponge granulomas was shown to depress in vitro phagocytosis by peritoneal macrophages. The glycoprotein had no effect on polymorphonuclear phagocytosis. Chemical and physical characterization of the inhibitor protein obtained from mature (42-day) granulomas developed in guinea pigs indicated that the protein had a molecular weight of 48,500 and an isoelectric point of 5.3. It was homogeneous when examined in three polyacrylamide disc gel electrophoretic buffer systems. The carbohydrate and amino acid content of the protein are reported. The chemical and physical characteristics of the inhibitor protein suggest that it is of nonserum origin. It is postulated that the glycoprotein inhibitor from chronic granulation tissue may participate in regulation of mononuclear phagocyte (macrophage) function within a local inflammatory focus.