The effect of neuropeptides/hormones on Langerhans cells

Neuropeptides/hormones have been shown to regulate the Various functions of many immunocompetent cells. A number of neuropeptides/hormones has been de monstrated to be present in the skin and a close anatomical association bet ween calcitonin gene-related peptide (CGRP)-containing nerves and Langerhan s cells (LC) has been reported. In addition to the CGRP receptor, receptors for several neuropeptides including pituitary adenylate cyclase activating polypeptide (PACAP) and gastrin releasing peptide (GRP) are found on LC, s uggesting these neuropeptides might have some effects on LC. CGRP inhibits alloantigen presentation and stimulation of a specific-antigen responsive T -cell clone by LC. Pre-treatment of LC with CGRP also inhibits the elicitat ion of delayed type hypersensitivity (DTH) in tumor immune mice. Upregulati on of B7-2 expression on LC is suppressed by CGRP, which might be, in part, responsible for the inhibitory effect of CGRP in the functional assay. The production of some inflammatory cytokines such as IL-10 by LC-like cell li ne XS52 is regulated by CGRP and the functional effect of CGRP appears to b e at least partially mediated through the autocrine regulation of IL-10. al pha-MSH is another neuropeptide, the effect of which has been well studied in the cutaneous immune system. Pre-treatment of mice with cl-MSH produces inhibitory effects in contact hypersensitivity (CHS). IL-10 has been sugges ted to be involved in the inhibitory effect of alpha-MSH. The receptors and the functional effects of other proopiomelanocortin (POMC)-derived peptide s including beta-endorphin and catecholamines on LC are under investigation . (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.