Open AccessDiscovery of an ancient MHC category with both class I and class II features
Author(s) -
Koji Okamura,
Johannes M. Dijkstra,
Keizou Tsukamoto,
Unni Grimholt,
G.F. Wiegertjes,
Akiko Kondow,
Hisateru Yamaguchi,
Keiichiro Hashimoto
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2108104118
Subject(s) - mhc class i , major histocompatibility complex , biology , mhc class ii , evolutionary biology , vertebrate , class (philosophy) , cd74 , genetics , immune system , gene , computer science , artificial intelligence
Significance Two classes of major histocompatibility complex (MHC) molecules, MHC class I and MHC class II, constitute the basis of our elaborate, adaptive immune system as antigen-presenting molecules. They perform distinct, critical functions: especially, MHC class I in case of antivirus and antitumor defenses, and MHC class II, in case of effective antibody responses. This important class diversification has long been enigmatic, as vestiges of the evolutionary molecular changes have not been found. The revealed ancient MHC category represents a plausible intermediate group between the two classes, and the data suggest that class II preceded class I in molecular evolution. Fundamental understanding of the molecular evolution of MHC molecules should contribute to understanding the basis of our complex biological defense system.