Enhancement of human lymphocyte natural killing function by non-opioid fragments of β-endorphin

Abstract

Opioid peptides have been shown to enhance peripheral blood lymphocyte natural killer (NK) cell function. In this study, we report that certain non-opioid fragments of beta-endorphin (2–16, 2–17, and 6–17) enhance NK activity with peak dose responses seen at 10 −12 to 10 −15 concentrations. This effect can be inhibited by naloxone. We conclude that non-opioid fragments of beta-endorphin are more potent than either beta- or gamma-endorphin in enhancing human lymphocyte NK activity.