Effects of beta-endorphin on phytohemagglutinin-induced lymphocyte proliferation and mouse plaque-forming cell response via an opioid receptor mechanism.

The effects of opioid peptides on immune responses were investigated. It was found that beta-endorphin (beta-END) can depress proliferative responses to PHA in rat splenocytes but enhance those in mice, and it could also inhibit the plaque-forming cell (PFC) response to sheep red blood cells when mouse splenocytes immunized in vivo were cultured in vitro with the peptide. The peptide antagonist naloxone was able to reverse beta-END suppression of the PFC response. The data indicate that beta-END suppresses antibody production or secretion via a specific opioid-receptor-mediated mechanism.