Influence of β-endorphin on phytohemagglutinin-induced lymphocyte proliferation and on the expression of mononuclear cell surface antigens in vitro

Francesco Puppo, Giovanni Corsini, Paola Mangini, Luigi Bottaro, Tommaso Barreca

Research output: Contribution to journalArticlepeer-review


Recent evidence suggests that opiates can modulate the immune responses. In particular it has been shown that β-endorphin and morphine are able to depress some T lymphocyte functions in humans. In the present study, experiments were designed to evaluate the effect of β-endorphin phytohemagglutinin-induced lymphocyte proliferation and determine the mechanism of this action. The ability of naloxone to block the effect of β-endorphin was also investigated, and the influence of β-endorphin on the expression of mononuclear cell surface antigens using the OKT3, OKT4, OKT8, anti-HLA-DR and anti-β2-microglobulin monoclonal antibodies was evaluated. Phytohemagglutinin-induced lymphocyte proliferation was significantly inhibited by β-endorphin. This effect occurred when β-endorphin was added to cells at the beginning of the culture period (30 min before, simultaneously or 30 min after phytohemagglutinin), but not when added after 48 h of incubation. The preincubation of cells with BEP for 1 h, 4 h or 24 h did not affect lymphocyte activation by phytohemagglutinin. A ten-fold excess of naloxone, added to cultures 30 min prior to β-endorphin, did not block the inhibitory effect. Incubation with β-endorphin had different effects on each surface antigen tested. The OKT8+ and β2-microglobulin+ cells did not show significant variations. The OKT4+ cells significantly decreased, after 4 h of incubation with β-endorphin, both in mononuclear cell and in purified T lymphocyte cultures and, after 24 h, in mononuclear cell cultures only. The OKT3+ cells decreased, in mononuclear cell cultures only, after 24 h β-endorphin incubation. The HLA-DR+ cells significantly increased after a 24 hr incubation period with β-endorphin in mononuclear cell cultures. These results demonstrate that β-endorphin inhibits phytohemagglutinin-induced lymphocyte proliferation, enhances the expression of HLA-DR antigen in mononuclear cells and reduces the expression of T3 and T4 antigens in T lymphocytes.

Original languageEnglish
Pages (from-to)119-125
Number of pages7
Issue number2
Publication statusPublished - 1985


  • Lymphocyte proliferation
  • Lymphocyte surface antigens
  • β-Endorphin

ASJC Scopus subject areas

  • Pharmacology


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