Morphine reciprocally regulates IL-10 and IL-12 production by monocyte-derived human dendritic cells and enhances T cell activation

Abstract

We evaluated the effect of morphine on human dendritic cells (DCs). Interestingly, immature DCs were found to express all 3 (μ, κ, δ) opioid receptors on the cell surface. Chronic morphine treatment (10 -8 to 10-12 M) during the development of DCs from monocytes augmented LPS-induced upregulation of HLA-DR, CD86, CD80, and CD83 and increased the T cell stimulatory capacity of DCs, which could be inhibited by naloxone, an opioid receptor antagonist. The change in surface phenotype was paralleled by a p38 MAPK-dependent decrease in IL-10 and increase in IL-12 secretion. Our data indicate that morphine exerts an immunostimulatory effect by modulating LPS-induced DC maturation.