]> 2026-07-31T07:50:12+00:00 WBR0055 0 en Combination of MHC class II and T-cell receptor (TCR) to stimulate leukocytes This is the mechanism of the Toxic Shock Syndrome (TSS) toxin by ''S. aureus'' and endotoxin A of ''S. pyogenes''. Because of their unique ability to stimulate leukocytes without co-stimulatory factors, these toxins are called "super antigens". Phospholipase ''Clostridium perfringens'' causes gas gangrene and produces the hemolytic alpha toxin, a zinc-containing phospholipase C enzyme (lecithinase) that preferentially degrades phophatidylcholine and sphingomyelin. Cleavage of SNARE protein Both botulinum and tetanus toxin cleave SNARE protein at synapses, thereby disabling neurotransmitter release at the synaptic cleft. Inactivation of 60S ribsosome by cleaving rRNA The toxins produced by ''Shigella'' and EHEC inactivate the 60S ribosome by cleaving rRNA. Increase of cAMP by intrinsic enzymatic activity Microbiology A 32-year-old male soldier suffers from an open leg wound following an explosion. He is immediately stabilized upon returning to the military base and is admitted for emergent surgery. Two days later, the patient develops high-grade fever with painful swelling and blisters at the wound site. CT scan of the involved leg is remarkable for gas formation in nearby muscles and subcutaneous tissue. What is the mechanism of action of the toxin responsible for this patient's complication? B Musculoskeletal/Rheumatology Infectious Disease 2020-10-27T23:10:49Z 2459150.4658449 WBR0055