NYMC Faculty Publications

Identification and Characterization of a High-Affinity Leukotriene B4 Receptor on Guinea Pig T Lymphocytes and Its Regulation by Lipoxin A4

Journal Title

The Journal of Pharmacology and Experimental Therapeutics

First Page

679

Last Page

684

Document Type

Article

Publication Date

May 1996

Department

Cell Biology

Abstract

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.

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