Co-expression of two LTB4 receptors in human mononuclear cells

Leukotriene B-4 (LTB4) is one of the most potent chemoattractants and activ ators of leukocytes, and is involved in inflammatory diseases. Two G-protei n-coupled-receptors for LTB4, BLT1 and BLT2, have been isolated, and shown to be a high- and low-affinity receptor, respectively. The tissue distribut ions of these receptors are different, and distinct roles of each receptor remain elusive. We compared the expression of these two receptors using sem i-quantitative PCR analyses, and show that these two receptors are expresse d in various subsets of human lymphocytes in different quantities. BLTI exp ression is highest in CD14(+) monocytes, while BLT2 expression is high in C D8(+) cytotoxic T-, CD4(+) helper T-, and CD19(+) B-cells. Moreover, BLT2 e xpression in these lymphocytes decreased upon activation of the cells. We a lso established CHO cells stably expressing both receptors, and found that these cells could migrate toward LTB4 with a broad range of LTB4. These fin dings suggest novel roles of LTB4 in immune system, and the biological sign ificance of high- and low- affinity LTB4 receptors in chemotaxis. (C) 2001 Elsevier Science Inc. All rights reserved.