Bacterial Pathogenesis

Question 1

Superantigens

Answer 1

Toxins produced by (particularly G+) bacteria

e.g. TSS caused by S. aureus (related to menstruation) but also sometimes by S. pyrogenes (rash, fever, hypotension and death in children)

Question 2

What is the mechanism of superantigen presentation?

Answer 2

• binds directly to MHC II
• does not get processed in the APC
• defining characteristic of superantigens is beta-chain specificity
  
  • binds to specific beta-chain T-cell receptors
  • ~20% of T-cells tf causes massive inflammatory response –> shock