Source Of Immunodominant MHC Associated Peptides (SIMP)

The SIMP protein contains a highly immunogenic minor histocompatibility antigen epitope of 9 amino acids, B6(dom1). Like ITM1, SIMP is homologous to yeast STT3, an oligosaccharyltransferase essential for cell proliferation .The B6(dom1) antigen corresponds to amino acids 770 to 778 of the 823-amino acid Simp protein, and analysis of cytotoxic T-lymphocyte activity in different mouse strains confirmed the presence of a polymorphism at amino acid 776. The 826-amino acid human protein shares 97% identity with the mouse protein. Sequence analysis of SIMP cDNA from 14 individuals failed to reveal polymorphism of human SIMP.