Mitogenic activation of the human lymphocytes induce the release of proenkephalin derived peptides

Several reports indicate that enkephalins participate in lymphocyte proliferation and several events of the immune response. It has been proposed that peptides involved in these processes may originate in the nervous system or endocrine glands. The authors have found that human peripheral blood lymphocytes (PBL) activated with a mitogenic agent contain and release proenkephalin derived peptides. The kinetics of met-enkephalin and cryptic products of proenkephalin in PBL activated with phytohemaglutinin (PHA) were studied. An intrinsic lymphocytic proenkephalin system is induced by PHA and may play an important role in the regulation of the immune response.