The role played by Major Histocompatibility Complex (MHC)-1 and -2 is to:(AlIMS November 2014, November 2013)

Ans. c. Present antigens for recognition by T-cell antigen receptors (Ref: Harrison 19/e p372e-1, 18/e p497; Ananthanarayan 8/e p132-135. 7/e p129)The role played by Major Histocompatibility Complex-1 and -2 is to present antigens for recognition by T cell antigen receptors. (AIIMS November 2013 repeat)"Main function of MHC molecule is to bind peptide fragments of foreign protein for presentation to appropriate antigen specific T cells.'Major Histocompatibility ComplexIn humans the gene encoding MHC or HLA complex are clustered on a small segment (4 megabase region) of chromosome 6 short armQ (6p 21.3)Q.HLA class I and class II genes whose products are critical for immunological specificity and transplantation histocompatibilityQ and they play a major role in susceptibility to a number of autoimmune diseases.Function: Binds peptide fragments of foreign protein for presentation to appropriate antigen specific T- CellsMHC is involved in* Transplantation reactionQ* Disease susceptibility (autoimmuneQ, infectious and inflammatory disease)* Immune response and tolerance* Complement component FeatureMHC-IMHC-IIMHC-lIIExpressed on (presented by)All nucleated cells and plateletsQAntigen presenting cells including Dendritic cellsQ in lymph node and spleen, Langerhans cellsQ, Macrophages, B cellsQ and activated T cellsQClass III is present in between I and IIEncoded by (component loci)3 closely linked loci designated HLA-A, HLA-B and HLA-CHLA-D (HLA DP, DQ, DR)C4B, BF, C2 TNF a and bEncoding moleculeCell surface glycoprotein involved in antigen presentationQCell surface glycoprotein Involved in antigen presentationQComponents of complement systemQRecognized byCD8+ T-cellsQ, NK cell recognitionCD4+ helper T-cellsQ FunctionImmune response against intracellular infection, tumors, allograftsQGraft rejectionQCell mediated cytolysisQComponent of hormone receptorQGraft versus host responseQMixed leucocyte reaction (MLR)Influence functional capacity of mature peripheral T cellsQ.