Identification and characterization of a high-affinity leukotriene B4 receptor on guinea pig T lymphocytes and its regulation by lipoxin A4
Lin, K.T.; Dudhane, A.; Godfrey, H.P.; Wong, P.Y.
Journal of Pharmacology and Experimental Therapeutics 277(2): 679-684
1996
ISSN/ISBN: 0022-3565 PMID: 8627545 Document Number: 455160
A single class of high affinity leukotriene B-4 (LTB-4) receptors has been identified on the surface of guinea pig peritoneal exudate T lymphocytes. The K-d of these receptors is 1.6 nM, with a B-max of 25.2 fmol/10-7 cells (1500 sites/cell). Receptor binding activity can be blocked by specific LTB-4 receptor antagonists, but not by a specific LTD-4 receptor antagonist, lipoxins A-4 or B-4 (LXA-4, LXB-4) or K252a, a protein kinase C inhibitor. Pretreatment of T lymphocytes with phorbol myristyl acetate or LXA-4, reduced LTB-4 receptor density in a concentration-dependent manner, although similar concentrations of LXB-4 had no effect. LTB-4 receptor down-modulation by LXA-4 was reversed by K252a. 4-alpha-Phorbol 12,13-didecanoate, an inactive structural analogue of phorbol myristyl acetate, did not activate protein kinase C or decrease LTB-4 receptor density. These results suggest that LTB-4 receptor density on T cells may be ultimately down-regulated by a protein kinase C-dependent mechanism and are consistent with a physiological role of LXA-4 in the modulation of inflammatory process.