tailieunhanh - Báo cáo khoa học: Gram-positive bacterial superantigen outside-in signaling causes toxic shock syndrome

Staphylococcus aureusand Streptococcus pyogenes(group A streptococci) are Gram-positive pathogens capable of producing a variety of bacterial exo-toxins known as superantigens. Superantigens interact with antigen-present-ing cells (APCs) and T cells to induce T cell proliferation and massive cytokine production, which leads to fever, rash, capillary leak and subse-quent hypotension, the major symptoms of toxic shock syndrome. | fFEBS Journal REVIEW ARTICLE Gram-positive bacterial superantigen outside-in signaling causes toxic shock syndrome Amanda J. Brosnahan1 and Patrick M. Schlievert2 1 Department of Veterinary and BiomedicalSciences College of Veterinary Medicine University of Minnesota Saint Paul USA 2 Department of Microbiology Medical School University of Minnesota Minneapolis USA Keywords MRSA mucosalimmunity Staphylococcus aureus Streptococcus pyogenes superantigen toxic shock syndrome Correspondence P. M. Schlievert Department of Microbiology Medical School University of Minnesota Minneapolis USA Fax 612 626 0623 Tel 612 624 1484 E-mail schli001@ Received 7 March 2011 revised 20 April 2011 accepted 27 April 2011 doi Staphylococcus aureus and Streptococcus pyogenes group A streptococci are Gram-positive pathogens capable of producing a variety of bacterial exotoxins known as superantigens. Superantigens interact with antigen-presenting cells APCs and T cells to induce T cell proliferation and massive cytokine production which leads to fever rash capillary leak and subsequent hypotension the major symptoms of toxic shock syndrome. Both S. aureus and group A streptococci colonize mucosal surfaces including the anterior nares and vagina for S. aureus and the oropharynx and less commonly the vagina for group A streptococci. However due to their abilities to secrete a variety of virulence factors the organisms can also cause illnesses from the mucosa. This review provides an updated discussion of the biochemical and structural features of one group of secreted virulence factors the staphylococcal and group A streptococcal superantigens and their abilities to cause toxic shock syndrome from a mucosal surface. The main focus of this review however is the abilities of superantigens to induce cytokines and chemokines from epithelial cells which has been linked to a dodecapeptide region that is relatively conserved among all superantigens and is .