Leukocyte Antigens of Rhesus Monkeys (RhL‐A) and Chimpanzees (ChL‐A): Similarities with the Human HL‐A System

The current state of tissue typing in Rhesus monkeys and chimpanzees is described. Data are presented, suggesting that the antigens of the Rhesus monkey's major histocompatibility system (RhL‐A) may well be controlled by two closely linked series of allelic genes, as is also the case for the human HL‐A system. Furthermore, methods for the production of typing reagents of high specificity by planned inter‐sib immunizations are described. For chimpanzees, advantages in the use of the complement‐fixation test are emphasized. Specificities previously established with a microcytotoxicity method seem to be better defined if the complement‐fixation test is used. The currently known specificities of the chimpanzee's major histocompatibility system (ChL‐A) were once again compared with the human HL‐A system. Several new similarities between both systems are reported. These similarities confirm the phylogenetic closeness between chimpanzee and man and reflect on the evolution of the human HL‐A system.