<prompt> The role played by major histocompatibility complex proteins MHC-1 and MHC-2 is to ?Transduce the signals to T cells following antigen recognitionMediate immunoglobulin class-switchingPresent antigens for recognition by T cell antigen receptorsEnhance the secretion of cytokines  <response>: Ans. is c i.e., Present antigens for recognition by T cell antigen receptorsThe histocompatibility antigens human leukocyte antigens - HLA are cell surface antigens that induce an immune response leading to rejection of allografts.o The principal physiologic function of the cell surface histocompatibility molecules is to bind peptide fragments of foreign proteins for presentation to antigen specific T cells.o The histocompatibility antigens are encoded by a closely linked multiallelic cluster of genes -- Major histocompatibility complex MHC or Human leukocyte antigens complex HLA complex.o HLA complex of genes is located on the sho arm of chromosome 6. 