Leukotriene B4 (LTB4) is a potent lipid mediator of allergic and inflammatory reactions, as well as a modulator of immune responses. Two receptors for LTB4 have been described on human neutrophils. The high-affinity human leukocyte LTB4 receptor, BLT1 mediates aggregation, chemotaxis, chemokinesis, and increased adherence to surfaces, whereas the low-affinity receptor, BLT2 (or LTB4R2) mediates degranulation and increased oxidative metabolism. BLT2 is expressed ubiquitously with the highest expression in spleen and has a broader ligand specificity for various eicosanoids. Cells expressing BLT2 exhibited LTB4-induced chemotaxis, calcium mobilization, and inhibition of adenylyl cyclase. BLT2 provides a novel target for anti-inflammatory therapy and promises to
expand our knowledge of LTB4 function.