title: Induction of leukochemotaxis by protein A of Staphylococcus aureus.
abstract: The mechanism of the leukochemotactic activity of staphylococcal protein A (pA) has been studied by in vitro and in vivo experiments. Protein A alone or mixed with heat-inactivated serum induced no migration of polymorphonuclear leukocytes, demonstrating that pA is not a cytotaxin, but a cytotaxigen. Protein A, activating both pathways of the C system, induced chemotaxis in a C4 deficient serum, but not in a C5 deficient serum. This shows that the chemotactic mediator elaborated is a split product of C5, i.e. C5a. The chemotactic activity of pA observed in the presence of normal sera (in vitro) and in wound chambers (in vivo) was exclusively caused by C activation via reaction with Fc.
mesh_terms: D000818:Animals; D001769:Blood; D002464:Cell Migration Inhibition; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D003167:Complement Activation / Q000187:drug effects; D003181:Complement C4 / Q000172:deficiency; D003182:Complement C5 / Q000172:deficiency; D003470:Culture Media; D006168:Guinea Pigs; D006801:Humans; D007958:Leukocyte Count; D051379:Mice; D009504:Neutrophils / Q000187:drug effects; D013205:Staphylococcal Protein A / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D003181:Complement C4; D003182:Complement C5; D003470:Culture Media; D013205:Staphylococcal Protein A