DISTRIBUTION OF U5 ANTIGEN ON LYMPHOCYTE SUBSETS IN HUMAN AND NONHUMAN-PRIMATES

The US monoclonal antibody developed by immunizing mice with Japanese monkey lymphocytes could react with lymphocytes of primate species inc luding Old World monkeys, apes, and human. However, the distributions of U5 antigen on major functional subsets of lymphocytes were differen t in primate species. The U5 antigen was mainly distributed on natural killer (NK) cells in human, but on B cells in Old World monkeys. On t he other hand, US antigen was detected on both B and NK cells in chimp anzees and gibbons, indicating that the distribution of US antigen on lymphocyte might change from B cells to NK cells during primate evolut ion.