Modulation of HLA-DR expression on CD14HIGH and CD14LOW monocytes by different neuromediators, cytokines, PGE
and ACTH. Blood samples from healthy donors were incubated for 24 hours without or with norepinephrine (NE, 10 nM), acetylcholine (AC, 10 μM), vasoactive intestinal peptide (VIP, 10 nM), pituitary adenylate cyclase-activating polypeptide (PACAP, 10 nM), substance P (SP, 1 μM), enkephalin (Enk, 1 μM), a mixture of all neuromediators, prostaglandin E2 (PGE2, 1 μM), adrenocorticotropin hormone (ACTH, 10 nM), transforming growth factor-β (TGF-β, 10 ng/ml), or tumor necrosis factor-α (TNF-α, 10 ng/ml). For both subpopulations, the results are expressed as the percent change of mean fluorescence intensity compared to HLA-DR measured in control cells. The results are the mean ± SEM of five independent experiments with different donors (* P < 0.05).