Effect of α-endorphin on the antigen-induced primary antibody response of human blood B cells in vitro

The interference of α-endorphin with the primary antibody response to ovalbumin (OA) of human blood lymphocytes in vitro was investigated. It was found that α-endorphin can block the OA-specific IgM-PFC response in a concentration of 0.05 to 0.5 μM. The decrease in the PFC response is due to an inhibitory effect of α-endorphin at the T cell level as well as at the B cell level. It appears that the neuropeptide is capable of blocking the production and/or secretion of antigen-specific T cell helper factor as well as of anti-OA antibodies by PFC. In addition, α-endorphin was shown to be capable of inhibiting the transition of B cells into PFC, which normally occurs after stimulation with antigen in the presence of adequate T cell helper activity. When α-endorphin, lacking the N-terminal amino acid residue tyrosine, is added to the cultures, inhibition of the PFC response is no longer observed. This indicates that α-endorphin influences the PFC response via opiate receptor interaction.