Cell mediated lysis of tumor cells is mediated by?
Correct Answer: HLA1
Description: Ans is 'a' i.e. HLA1 * HLA complex consists of three separate clusters of genes :-1) Class I (MHC-I)# It comprising of A, B and C loci (i.e. HLA-A, HLA-B, HLA-C). It is found on the surface of all nucleated cells and platelets.# Important cells with MHC-I (HLA-I) on surface are B-cells, T-cells, macrophages/monocytes, neutrophils, langerhans cells, dendritic cells, platelets (thrombocytes), epithelial cells of thymus and hepatocytes. MHC class I present antigen to cytotoxic CD-8 T cells (MHC-I restricted).# MHC class I is responsible for graft rejection and cell mediated cytolysis of viral infected or tumor cells.2) Class II (MHC-II)# It comprises 'D' region (HLA-DR, HLA-DQ, HLADP). It is found only on the cells of immune system, i.e. T-cells, B-cells, langerhans cells, dendritic cells, and macrophages.# MHC-II recognizes exogenous antigen (extracellular microbes, soluble proteins) and present it to CD4 helper T cells (MHC-II restricted). MHC-II is responsible for graft versus host response and mixed leukocyte reaction.3) Class III (MHC-III)# It encodes for complement components C2 & C4, properdin factor B, Heat shock protein and Tumor necrosis factor-a and b (TNF-a and b). MHC-III is involved in susceptibility to autoimmune diseases like SLE.
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