Nomenclature for the major histocompatibility complexes of different species: a proposal

Abstract

The major histocompatibility complex (MHC) has been given different names in different species (Klein 1986). It is designatedH-2 in the mouse, HLA in humans, B in the domestic fowl, RT1 in the rat, and Smh in the mole rat. In most other species that have been studied, the MHC is referred to by the LA symbol (for lymphocyte or leukocyte antigen), prefixed by an abbreviation of the species’ common name. Thus, it is called ChLa in the chimpanzee, GoLA in the gorilla, RhLA in the rhesus macaque, RLA in the rabbit, BoLA in the domestic cattle, SLA in the pig, and so on. This practice has two problems associated with it. First, MHC products are expressed on many other tissues in addition to lymphocyte or leukocyte (and lymphocytes express many other antigens in addition to those controlled by the MHC) and their antigenicity is secondary to their biological function. Second, the use of common names to identify a species is a potential source of confusion. Common names are notoriously vague and imprecise. The designation “lemur”, for example, can refer to any of the genera Lemur, Hapalemur, Varecia, Lepilemur; Avahi, Propithecus, and Indri, of which only the first four belong to the family Lemuridae; the last three are members of the family Indriidae. A “bushbaby” can be a Galago, Otolemur, or Euoticus. A “mouse” could be a Notomys, ylcomys, Uranomys, Pogomys, Chiruromys, Chiropodomys, Neohydromys, and so on. Obviously, common names not only fail to identify the species appropriately, they often do not even identify the genes or the family. If the trend in choosing common names for MHC symbols were to continue, chaos would soon ensue because we can expect MHCs in many different species to be identified in the future.