Expression of the cysteinyl leukotriene 1 receptor in normal human lung and peripheral blood leukocytes

The cysteinyl leukotrienes (CysLTs) are important mediators of human asthma. Pharmacologic and clinical studies show that the CysLTs exert most of their bronchoconstrictive and proinflammatory effects through activation of a putative, 7-transmembrane domain, C-protein-coupled receptor, the CysLT(1) receptor. The initial molecular characterization of the CysLT(1) receptor showed by in situ hybridization, the presence of CysLT(1) receptor messenger RNA (mRNA) in human lung smooth-muscle cells and lung macrophages. We confirmed the results of these in situ hybridization analyses for the CysLT(1) receptor, and produced the first immunohistochemical characterization of the CysLT(1) receptor protein in human lung. The identification of the CysLT(1) receptor in the lung is consistent with the antibronchoconstrictive and antiinflammatory actions of CysLT(1) receptor antagonists. We also report the expression of CysLT(1) receptor mRNA and protein in most peripheral blood eosinophils and pregranulocytic CD34(+) cells, and in subsets of monocytes and B lymphocytes.