Leukotriene B4 receptor BLT1 mediates early effector T cell recruitment.

Leukotriene B4 (LTB4) was originally described as a potent lipid myeloid cell chemoattractant, rapidly generated from innate immune cells, that activates leukocytes through the G protein-coupled receptor BLT1. We report here that BLT1 is expressed on effector CD4+ T cells generated in vitro as well as in vivo when effector T cells migrate out of the lymphoid compartment and are recruited into peripheral tissues. BLT1 mediated LTB4-induced T helper type 1 (T(H)1) and T(H)2 cell chemotaxis and firm adhesion to endothelial cells under flow, as well as early CD4+ and CD8+ T cell recruitment into the airway in an asthma model. Our findings show that the LTB4-BLT1 pathway is involved in linking early immune system activation and early effector T cell recruitment.