VIP Protects Th2 Cells by Downregulating Granzyme B Expression
Selective differentiation of Th1/Th2 effectors contributes to cell- or antibody-mediated immunity. Vasoactive intestinal peptide (VIP) induces Th2 responses by promoting Th2 differentiation and survival. Here we investigate the mechanisms of VIP-induced Th2 survival. Microarray and protein data indicate that VIP prevents the upregulation of granzyme B (GrB) in Th2, but not Th1 effectors. This is the first report of GrB expression and of its involvement in activation-induced apoptosis of T helper cells. The enhanced responsiveness of Th2 cells to VIP is probably due to the higher expression of VIP receptors and alternative signaling pathways. This study identifies GrB as a new significant player in Th1/Th2 activation-induced cell death, and characterizes the mechanisms for the protective effect of VIP on Th2 survival
granzyme b vasoactive intestinal peptide th1/th2 differentiation t cell apoptosis