Staphylococcal enterotoxins B (SEB) is described as a superantigen for its ability to bind to Major Histocompatibility Complex molecules on antigen presenting cells and stimulate a large population of T cells, producing an inappropriate flood of cytokines. Although they are important participants in an immune response, cytokines, when overproduced, lead to toxic shock. Recently SEB has been found to bind to another regulator of the T cell immune response, CD 28. When added to human peripheral blood cells, SEB produces large quantities of IL-2, TNF-A and INF-c. Native SEB toxin has been treated with formaldehyde to produce a toxoid which has reduced cytokine stimulating activity and immunogenicity when compared with the native toxin. Care must be taken in the design of experiments with the toxoid because although toxicity has been reduced, sufficient toxicity may remain to cause death under certain conditions. Both the toxin and toxoid are handled as Select Agents and Toxins.
More information about SEB can be found on our blog.