The vascular hyperpermeability and bronchoconstriction observed in BLT2-KO mice after PLY administration resemble a lethal asthma attack in a human patient; thus, we hypothesized that these characteristics may be linked to bronchoconstrictors such as cysteinyl leukotrienes (cysLTs; leukotriene C4 (LTC4), leukotriene D4 (LTD4) and leukotriene E4 (LTE4)), collectively known as slow reactive substance of anaphylaxis (SRS-A)20. Here, LTB4R2 is linked to asthma.