Immunomodulatory responses to delta-opioid receptor ligands in human lymphocytes.

In phytohemagglutinin (PHA) activated human peripheral blood mononuclear cells. [3H]thymidine uptake and interferon gamma production were increased by the delta-opioid receptor agonist, deltorphin-I (10(-14)-10(-10) M) and by the delta-opioid antagonist naltrindole (10(-13)-10(-9) M). Combination of 10-9 M naltrindole with deltrophin-I (10(-12)-10(-8)M) significantly inhibited the proliferative response but did not affect interferon production.