VIP: a very important peptide in T helper differentiation

Vasoactive intestinal peptide (VIP), a neuropeptide mainly produced by Th2 cells following antigenic stimulation, has a general anti-inflammatory effect, both in innate and adaptive immunity. Recent studies indicate that lymphocyte-derived VIP acts as an important T helper-differentiating factor, promoting Th2-type, and inhibiting Th1-type responses, through several mechanisms, including preferential survival of Th2 effectors and generation of memory Th2 cells. These effects appear to be responsible for the beneficial effect of VIP in models of Th1-type autoimmune diseases, such as rheumatoid arthritis and Crohn's disease.