DIFFERENTIAL EXPRESSION OF VASOACTIVE-INTESTINAL-PEPTIDE RECEPTOR-1 AND RECEPTOR-2 (VIP-R1 AND VIP-R2) MESSENGER-RNA IN MURINE LYMPHOCYTES

Vasoactive intestinal peptide (VIP), a neuropeptide present in the lym phoid microenvironment, modulates cytokine expression and affects T ce ll proliferation. Recent molecular studies identified two VIP receptor s, VIP-R1 and VIP-R2, primarily in nonlymphoid cells. In this study, w e 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 expresse d, the expression of VIP-R2 is induced only following stimulation thro ugh the TCR-associated CD3 complex. Both CD4(+) and CD8(+) T cells exp ress VIP-R1 and VIP-R2. Two T cell lines, EL-4.IL-2 and D10.G4.1 expre ss exclusively VIP-R2. VIP induces the expression of the VIP-R2 gene i n the absence of additional stimuli. Differential expression and regul ation of the two VIP receptors in T lymphocytes suggests different phy siological roles in mediating the immunomodulatory activities of VIP a nd related neuropeptides.