Measurement of staphylococcal protein A and detection of protein A-carrying staphylococcus strains by a competitive ELISA method.
A competitive ELISA for the estimation of staphylococcal protein A is described. Tetanus toxoid is insolubilized on polystyrene and incubated with human antitoxin, which renders the Fc-piece of this antibody freely accessible to protein A. The binding of the latter is demonstrated by its competition with protein A-phosphatase conjugate. The method has been shown to be sensitive and reproducible. It has been used for the detection of protein A in culture supernatants and on living pathogenic staphylococci. The test could therefore be of diagnostic value. Protein A is also present in extracts of food contaminated with enterotoxic staphylococci. It can be eliminated by a simple absorption with insoluble porcine IgG.
D000818:Animals; D000992:Antitoxins / Q000494:pharmacology; D001667:Binding, Competitive; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D011817:Rabbits; D013205:Staphylococcal Protein A; D013211:Staphylococcus aureus / Q000032:analysis*; D013552:Swine
D000992:Antitoxins; D013205:Staphylococcal Protein A