Which of the following is a superantigen
Correct Answer: TSST
Description: Superantigens
Certain species of infectious microorganisms produce powerful,
immunostimulatory and disease-causing toxins called superantigen, so called because of their ability' to a polyclonally active large fraction ( up to 20% ) of T cell population.
Superangens are potent acvators of T-lymphocytes.
Superangens smulate very large numbers of T cells, without relaon to their epitope specificity'.
This leads to an excessive and dysregulated immune response with release of cytokines IL - 1, IL - 2, TNF - α and IF - γ.
Conventional antigens bind to MHC class I or II molecules in the groove
of the β dimer (T cell receptor). In contrast, superantigen bind directly to the lateral portion of TCR β chain and MHC class II β chain, and stimulate T cells solely on γ β gene segment utilized
independent of the D, J and γ aα - sequences present → γ β restricted T cell mitogens.
Superantigens are capable of giving up to 20% of the peripheral T-cell pool,
whereas conventional antigens activate < 1 in 10, 000.
Examples of superantigen Staphylococcal toxic shock syndrome toxin □ Certain nonhuman retroviral proteins,
Staphylococcal enterotoxins □ Yersinia pseudotuberculosis Staphylococcal exfoliative (erythrogenic) toxin □ Mycoplasma arthritis. Streptococcal toxic shock syndrome toxin □ Mouse mammary tumor virus.
Category:
Microbiology
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