The Role of Complement in Immune Phagocytosis of Group A Streptococci by Mouse Peritoneal Phagocytic Cells

Abstract

The role of complement in ingestion of nonencapsulated virulent group A streptococci by mouse peritoneal phagocytic cells was studied in vitro in the presence of type‐specific IgG or IgM anti‐M antibody. Type‐specific IgG anti‐M antibody significantly enhanced the phagocytosis, whereas IgM antibody was less effective in opsonization of the virulent group A streptococci. The extent of phagocytosis of streptococci sensitized with IgG or IgM anti‐M antibody was not influenced by the presence of complement. These results suggested that complement was not an essential factor for efficient phagocytosis of virulent group A streptococci.