Toxins 2010, 2, 2177-2197; doi:10.3390/toxins2082177 OPEN ACCESS toxins ISSN 2072-6651 www.mdpi.com/journal/toxins Review Staphylococcal Enterotoxins Irina V. Pinchuk 1, Ellen J. Beswick 2 and Victor E. Reyes 3,* 1 Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-0655, USA; E-Mail:
[email protected] 2 Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, NM 87131, USA; E-Mail:
[email protected] 3 Departments of Pediatrics and Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555-0366, USA * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel.: +1-409-772-3824; Fax: +1-409-772-1761. Received: 29 June 2010; in revised form: 9 August 2010 / Accepted: 12 August 2010 / Published: 18 August 2010 Abstract: Staphylococcus aureus (S. aureus) is a Gram positive bacterium that is carried by about one third of the general population and is responsible for common and serious diseases. These diseases include food poisoning and toxic shock syndrome, which are caused by exotoxins produced by S. aureus. Of the more than 20 Staphylococcal enterotoxins, SEA and SEB are the best characterized and are also regarded as superantigens because of their ability to bind to class II MHC molecules on antigen presenting cells and stimulate large populations of T cells that share variable regions on the chain of the T cell receptor. The result of this massive T cell activation is a cytokine bolus leading to an acute toxic shock. These proteins are highly resistant to denaturation, which allows them to remain intact in contaminated food and trigger disease outbreaks.