How did the primordial T cell receptor and MHC molecules function initially?
Two genes, designated Trsc-UAA and Trsc-UBA, which encode highly polymorphic major histocompatibility complex (MHC) class I molecules in the shark Triakis scyllia were isolated. The identification of these genes indicates that the classical MHC class I was already established at the level of elasmobranchs during animal evolution. At the emergence of the MHC/T cell receptor recognition system, the number of genes for T cell receptors (TCR) must have been just one. In this brief review, the way in which a small number of TCR could have recognized MHC-oligopeptide complexes initially, based on recent progress in the phylogenetic analysis of the immune systems in primitive vertebrates, is discussed.
Kurosawa
Y
Y
Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan. kurosawa@fujita-hu.ac.jp
Hashimoto
K
K
D000818:Animals; D015329:Gene Rearrangement, T-Lymphocyte / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D007111:Immunity, Cellular; D010802:Phylogeny; D011110:Polymorphism, Genetic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D012754:Sharks / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology
D015395:Histocompatibility Antigens Class I; D011948:Receptors, Antigen, T-Cell