Author(s): Delgado M, Martinez C, Johnson MC, Gomariz RP, Ganea D
Vasoactive intestinal peptide (VIP), a neuropeptide present in the lymphoid microenvironment, modulates cytokine expression and affects T cell proliferation. Recent molecular studies identified two VIP receptors. VIP-R1 and VIP-R2, primarily in nonlymphoid cells. In this study, we investigate the expression of VIP-R1 and VIP-R2 mRNA in unstimulated and stimulated lymphocytes and thymocytes, and in various lymphocyte subpopulations. In contrast to VIP-R1 which is constitutively expressed, the expression of VIP-R2 is induced only following stimulation through the TCR-associated CD3 complex. Both CD4+ and CD8+ T cells express VIP-R1 and VIP-R2. Two T cell lines, EL-4.IL-2 and D10.G4.1 express exclusively VIP-R2. VIP induces the expression of the VIP-R2 gene in the absence of additional stimuli. Differential expression and regulation of the two VIP receptors in T lymphocytes suggests different physiological roles in mediating the immunomodulatory activities of VIP and related neuropeptides.