Identification and Characterization of a High-Affinity Leukotriene B4 Receptor on Guinea Pig T Lymphocytes and Its Regulation by Lipoxin A4
A single class of high affinity leukotriene B4 (LTB4) receptors has been identified on the surface of guinea pig peritoneal exudate T lymphocytes. The Kd of these receptors is 1.6 nM, with a Bmax of 25.2 fmol/10(7) cells (1500 sites/cell). Receptor binding activity can be blocked by specific LTB4 receptor antagonists, but not by a specific LTD4 receptor antagonist, lipoxins A4 or B4 (LXA4, LXB4) or K252a, a protein kinase C inhibitor. Pretreatment of T lymphocytes with phorbol myristyl acetate or LXA4, reduced LTB4 receptor density in a concentration-dependent manner, although similar concentrations of LXB4 had no effect. LTB4 receptor down-modulation by LXA4 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 LTB4 receptor density. These results suggest that LTB4 receptor density on T cells may by ultimately down-regulated by a protein kinase C-dependent mechanism and are consistent with a physiological role of LXA4 in the modulation of inflammatory process.
Lin, K. T., Dudhane, A., Godfrey, H., & Wong, P. (1996). Identification and Characterization of a High-Affinity Leukotriene B4 Receptor on Guinea Pig T Lymphocytes and Its Regulation by Lipoxin A4. The Journal of Pharmacology and Experimental Therapeutics, 277 (2), 679-684. Retrieved from https://touroscholar.touro.edu/nymc_fac_pubs/1741