Which is not true regarding superantigen
Correct Answer: Bind to cleft (antigen binding groove) in the MHC II molecule
Description: 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
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now