Which of the following is a superantigen

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.