Mouse anti-Human PTGIR monoclonal antibody, clone 5C20

Prostaglandins (PGD(2), PGE(2), PGF(2 alpha), and PGI(2)) and thromboxane A(2) (TXA(2)) are biologically active molecules derived from the metabolism of arachidonic acid by cyclooxygenases. They produce a wide variety of physiological and pathophysiological effects mediated through specific G protein-coupled cell surface receptors. In this study, we have mapped the chromosomal positions of the human genes that encode the PGE(2) receptor subtypes (PTGER1, PTGER2, and PTGER3), the PGF(2 alpha) receptor (PTGFR), the PGI(2) receptor (PTGIR), and the TXA(2) receptor (TBXA2R) using in situ hybridization. The PTGER1, TBXA2R, and PTGIR genes mapped to chromosome 19 at positions 19p13.1, 19p13.3, and 19q13.3, respectively. The PTGFR and PTGER3 genes mapped to chromosome 1 at positions 1p31.1 and 1p31.2, respectively, and PTGER2 gene mapped to chromosome band 5p13.1. (C) 1995 Academic Press, Inc.

PGI(2), which exerts its actions via its specific Gs-coupled I prostanoid receptor (IP), is known to be present in the lymph nodes, but its roles in acquired cutaneous immune responses remain unclear. To investigate the role of PGI(2) IP signaling in cutaneous immune responses, we applied IP-deficient (Ptgir(-/-)) mice to contact hypersensitivity as a model of acquired immune response and found that Ptgir(-/-) mice exhibited a significantly decreased contact hypersensitivity response. Lymph node cells from sensitized Ptgir(-/-) mice exhibited decreased IFN-gamma production and a smaller T-bet(+) subset compared with control mice. PGI synthase and IP expression were detected in dendritic cells and T cells, respectively, by quantitative real-time PCR analysis, suggesting that PGI(2) produced by dendritic cells acts on IP in T cells. In fact, in vitro Th1 differentiation was enhanced by an IP agonist, and this enhancement was nullified by protein kinase A inhibitor. These results suggest that PGI(2) IP signaling promotes Th1 differentiation through a cAMP-protein kinase A pathway and thereby initiates acquired cutaneous immune responses. The Journal of Immunology, 2010, 184: 5595-5603.