title: Activation of complement by cell surface components of Staphylococcus aureus.
abstract: The abilities of intact Staphylococcus aureus H, crude cell walls (CCW), purified cell walls (PCW, peptidoglycan [PG] and covalently linked teichoic acid), peptidoglycan, and cell membranes (CM) to activate the complement system in normal human serum, C2-deficient serum, and immunoglobulin-deficient serum were compared. On a weight basis, PCW was the most active fraction; intact organisms and CCW were about equally effective; and PG was least active in causing complement consumption in normal serum. CM also activated complement but did not give a clear dose-response relationship in the concentrations used. Kinetic studies revealed that C3-C9 consumption occurred at a significantly slower rate in C2-deficient serum, indicating that intact organisms, PCW, and PG may activate the complement system via the classical and alternative pathways in normal serum. C3-C9 consumption was also slower in immunoglobulin-deficient serum than in normal serum, implying that immunoglobulins play a role in attaining maximum rates of complement activation. In all sera studied, PG was less active in complement activation than PCW. These results indicate that a number of cell surface components of S. aureus can play a role in complement activation by this organism and that the presence of teichoic acid has a significant enhancing effect in this regard.
mesh_terms: D002462:Cell Membrane / Q000032:analysis / Q000276:immunology; D002473:Cell Wall / Q000032:analysis / Q000276:immunology; D003175:Complement C2 / Q000172:deficiency; D003165:Complement System Proteins / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D010457:Peptidoglycan / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology* / Q000648:ultrastructure; D013682:Teichoic Acids / Q000276:immunology
chemical_list: D003175:Complement C2; D010457:Peptidoglycan; D013682:Teichoic Acids; D003165:Complement System Proteins