Bacteria producing superantigens?

Bacteria producing superantigens?

• A. Streptococcus pyogenes and Staphylococcus aureus
• B. Streptococcus pneumoniae and Staphylococcus aureus
• C. Escherichia coli and Streptococcus pyogenes
• D. Mycobacterium tuberculosis and Streptococcus pyogenes

Answer: (A)

Superantigens activate a large fraction of T cells by bypassing normal antigen processing. They bind simultaneously to MHC class II molecules on antigen-presenting cells and to the Vβ region of the T cell receptor, outside the peptide groove. This non-specific cross-linking triggers massive T cell activation and a cytokine storm, releasing IL-1, IL-2, TNF-α, and IFN-γ, which can lead to toxic shock with fever, rash, and hypotension. Staphylococcus aureus produces TSST-1 and various enterotoxins that act as superantigens. Streptococcus pyogenes (Group A Streptococcus) produces pyrogenic exotoxins such as SpeA and SpeC that also function as superantigens. The other listed organisms do not typically produce classic superantigens. So, the bacteria known for producing superantigens are Staphylococcus aureus and Streptococcus pyogenes.

Superantigens activate a large fraction of T cells by bypassing normal antigen processing. They bind simultaneously to MHC class II molecules on antigen-presenting cells and to the Vβ region of the T cell receptor, outside the peptide groove. This non-specific cross-linking triggers massive T cell activation and a cytokine storm, releasing IL-1, IL-2, TNF-α, and IFN-γ, which can lead to toxic shock with fever, rash, and hypotension.

Staphylococcus aureus produces TSST-1 and various enterotoxins that act as superantigens. Streptococcus pyogenes (Group A Streptococcus) produces pyrogenic exotoxins such as SpeA and SpeC that also function as superantigens. The other listed organisms do not typically produce classic superantigens. So, the bacteria known for producing superantigens are Staphylococcus aureus and Streptococcus pyogenes.