<prompt> Superantigen causes-Polyclonal activation of T-cellsStimulation of B cellsEnhancement of phagocytosisActivation of complement  <response>: 1.Superantigensare a class of molecules that can interact with APCs and T lymphocytes in a nonspecific wayattach to TCR by the side not in tne centre . The superantigens act differently by interacting with MHC class II molecules of the APC and the Vb domain of the T-lymphocyte receptor. This interaction results in the polyclonal activation of a larger number of T cells 10 than conventional antigens 1, leading to massive cytokine expression and immunomodulation. fig:-Mechanism of action of superantigen 2. Examples: Staphylococcal toxin: TSST, Exfoliative toxin, Enterotoxins, Streptococcal toxin: Streptococcal pyrogenic exotoxin SPE-A Viral: EBV, CMV, Rabies nucleocapsid, HIV encoded nef negative regulatory factor Fungal superantigen: Malassezia furfur 