Which is not true regarding superantigen

Superantigens are polyclonal T-lymphocyte activators that induce the release of high levels of cytokines that result in a variety of clinical manifestations, ranging from a diffuse rash to vasodilation, hypotension, shock, and death.Superantigens are bacterial toxins that stimulate a very large number of T lymphocytes by binding to conserved poions of the T-cell receptor, leading to massive T-lymphocyte proliferation and cytokine release. The high levels of cytokines can lead to capillary leak and shock. Superantigens made by S. aureus and S. pyogenes cause toxic shock syndrome (TSS).Superantigens do not require processing and therefore are able to bind to MHC II molecules outside the peptide-binding cleft.TSST-1 stimulates most T-cells by binding directly to MHC-II and T-cell receptors. The net result is the production of large amounts of the cytokinesinterleukin-2 (IL-2), interferon g, and tumor necrosis factor (TNF).Reference: Jawetz Melnick and Adelbergs Medical Microbiology; 27th edition; Chapter 8; Immunology