Indirect visualization of Staphylococcus aureus protein A.
Specific but nonimmunologic reaction between staphylococcal protein A and the Fc portion of gamma globulin provided the basis for ultrastructural studies to determine the localization of protein A, using intact staphylococci and labeled myeloma gamma G-globulin. Protein A appeared to be part of the outermost layer of the staphylococcal cell wall. Strains with protein A demonstrated a coating of myeloma globulin over the entire bacterial surface. There was no coating of strains without protein A. Identification of protein A on the surface of the staphylococcal cell wall provides evidence that this may be the first material in contact with host environment. It probably accounts for apparent cross-reactions of staphylococci with antibodies to many antigens. More importantly, even in the nonimmune host protein A immunoglobulin reactivity may initiate complement activation and inflammatory reactions including chemotaxis and pus formation.
D001426:Bacterial Proteins / Q000032:analysis*; D002473:Cell Wall / Q000276:immunology*; D006651:Histocytochemistry; D007120:Immunochemistry; D007074:Immunoglobulin G; D008854:Microscopy, Electron; D013210:Staphylococcus / Q000166:cytology* / Q000276:immunology
D001426:Bacterial Proteins; D007074:Immunoglobulin G