Modulation of the immune response by tachykinins

Abstract

Summary Neuro‐immunology is becoming an increasingly important discipline of immunology. This review has examined the immunomodulatory function of one group of neuropeptides, the TK, particularly SP and NKA. These peptides are localized in primary afferent nerves which have been shown to innervate several immune organs. In addition, binding sites for the TK have been demonstrated in thymus, spleen and lymph node. Several immune cell types also express neurokinin receptors including human circulating lymphocytes with binding to the Th/i class predominating, murine T and B cells, a human T lymphoblastoid cell line, human monocytes, rabbit polymorphonuclear leucocytes and guinea‐pig macrophages. The apposition of nerves with immune cells and receptors for neuropeptides thus produces an environment for interaction between the nervous and immune systems. Studies in vitro and, more recently, in vivo have examined how the TK regulate immune cell responses. The TK stimulate proliferation of T cells, enhance mitogen‐induced release of cytokines including IFN‐γ, TNF‐α, IL‐1 and IL‐6 from mononuclear cells and macrophages, enhance immunoglobulin secretion and affect cellular chemotaxis and phagocytosis. Studies in vivo have shown a role for TK in lymphocyte recirculation of sheep lymph nodes, reversal of stress‐induced thymic involution and Ig production in both rat and mouse. Many of these effects appear to be mediated via NK‐2 type receptors. To date, most of the work has involved studies in vitro, but the results from these are now being validated by studies in vivo where both the immune system and neuropeptides are able to interact at many anatomical sites. The complexities of the immune and the nervous systems mean that only a small number of potential interactions has been examined. Future studies can be expected to amplify these observations, especially with respect to the understanding of inflammatory and immune diseases in humans.

Sensory nerves in the interface membrane of aseptic loose hip prostheses

“…22 blasts, lymphocytes and macrophages are equipped with SP and NKA receptors and SP has been shown to induce the release of IL-1, IL-6 and TNF-␣ from these cells. 48,49 SP has also been reported to promote inflammatory cell chemotaxis, 50 fibroblast proliferation 51 and antibody formation. 52 Furthermore, it has been shown that SP enhances the secretion of prostaglandin E 2 and collagenase in synoviocytes 53 and that CGRP stimulates lymphocyte proliferation.…”

Immune Defense Mechanisms of the Dental Pulp

“…Besides the actions on the microcirculation, several recent investigations have provided evidence that neuropeptides can influence the activities of diverse inflammatory and immunocompetent cells through receptor-mediated mechanisms (reviewed by Eglezos et al, 1991;McGillis et al, 1991). SP in general acts as an immunostimulatory agent.…”

Pharmacological effects of fermented red pepper

“…SP plays an important role in the regulation of several immune responses. Both in vivo and in vitro studies have indicated that SP stimulates macrophage phagocytosis (Hartung et al, 1986), and T and B lymphocyte proliferation and effector functions (Eglezos et al, 1991).…”