PubMed · 1981 · 45 citations · 0 references
Veterinary MedicineMicrobiologyDiagnostic MicrobiologyFood MicrobiologyImmunology Of Infectious DiseasesAntigen Detection AssaysBacterial ToxinsEnzyme-linked Immunosorbent AssayFoodborne Pathogen DetectionImmunoassay AnalysisPathogen DetectionAnalytical Methods For Food ToxinsBacterial Toxin AssaysFalse Positive ReactionsMethod Detection LimitSandwich Enzyme-linked Immunosorbent AssayStaphylococcal EnterotoxinsStaphylococcus Aureus DetectionToxin Detection Assays
Staphylococcus aureus enterotoxins A, B, and C, were detected by means of a four-layer sandwich ELISA method. With toxin produced in broth supernatants, this ELISA method had a detection limit of 0.5 ng enterotoxin per ml. Conjoint with enterotoxin, S. aureus most often produces protein A. The protein A will interfere and produce false positive reactions in a sandwich ELISA, by binding nonspecifically the IgG in different layers, simulating the immunospecific toxin binding. With rabbit IgG coupled to Sepharose CL-4B gel, 99% of protein A could be removed from solutions, bringing the level under the interfering limit in the ELISA.