Cloning and characterization of rat leukotriene B-4 receptor

Leukotriene B-4 (LTB4) is a potent chemoattractant for neutrophils and eosi nophils. cDNAs for LTB4 receptor (BLT) have been cloned from human, mouse, and guinea pig. Here we report the isolation of BLT from rat genomic librar y. Rat BLT consists of 351 amino acids with homologies of 80.2, 93.2, and 7 1.6%, to human, mouse, and guinea pig BLT, respectively. When expressed in human embryonic kidney (HEK)-293 cells, rat BLT showed a specific and high- affinity binding to LTB4 with a Kd value of 0.68 nM (mean, n = 3). Northern blot analysis showed that BLT is exclusively expressed in polymorphonuclea r leukocytes. Furthermore, the expression of BLT was high in proteosepepton e-activated peritoneal macrophages, while the resident macrophages did not show significant expression. The present results suggest important roles of LTB4 in macrophage recruitment and activation. (C) 1999 Academic Press.