Superantigens

Question 1

What are superantigens?

Answer 1

Exotoxins, produced intracellulalyr and secreted as mature cellular exotoxins. Superantigens bind MHC-2 and then bind the T-cell receptor of T-cells (esp. Th1 cells)

Question 2

Describe superantigen cascade

Answer 2

• Superantigen activation of Th1 cells also causes Th1 cells to express CD40 ligand, which binds the CD40 receptor of B-cells and activates their isotype switching from IgM🡪IgE or IgG
• Activated T-cells secrete IFN-gamma, which activates macrophages, which produce more inflammatory cytokines (IL-1, IL-6, TNF-a)
• Activated T-cells secrete massive amounts of cytokines🡪cytokine storm
• Recruit neutrophils by activating monocyte, which secrete TNF-alpha, which recruits leukocytes
• Activate endotoxins