CONICET | Buscador de Institutos y Recursos Humanos

Staphylococcal enterotoxins are one of the most important causative agents of food poisoning.They function both as gastrointestinal toxins as well as superantigens (SAgs) which can simultaneously bind MHC II and T-cell receptor leading to a non-specific polyclonal T cell activation and massive pro inflammatory cytokine release. Common symptoms include vomiting and diarrhea, however, in more severe cases, systemic dissemination may result in toxic shock syndrome and can be lethal in a few hours. Only small amounts of these heat-stable toxins are needed to cause the disease. Therefore, it is highly important to detect low concentrations of SAgs in any biological sample. Classical methods such as ELISA or Western blotting can detect SAgs, but they do not provide real-time information. In order to find a rapid, sensitive and specific method for the detection of SAgs, we developed a Surface plasmon resonance (SPR) sensor system based on a double antibody sandwich approach using a Biacore T100 instrument. Polyclonal specific antibodies were covalently coupled on the chip surface, where the toxin is captured from a liquid sample and subsequently, secondary antibodies are run in solution enabling the corresponding signal amplification. We analyzed different quantities of immobilized antibodies on independent sensor chips and demonstrated that in the best condition the SAg was detectable at picomolar levels (1.10-12M), much lower compared to other immunoassays. We also studied the potential use of antibody-coated Nanoparticles (NPs) as an alternative amplification strategy. SPR biosensors offer the capability for continuous real-time monitoring and high sensitivity that can be befitting for the detection of enterotoxins in food industries, laboratories and regulatory agencies.