Leukotriene Receptor Antibodies

The leukotriene receptor family comprises four principal class A G protein-coupled receptors, BLT₁, BLT₂, CysLT₁, and CysLT₂. BLT₁ is a high-affinity receptor for leukotriene B₄ (LTB₄), whereas BLT₂ responds to LTB₄ with lower affinity and is potently activated by 12-hydroxyheptadecatrienoic acid (12-HHT). CysLT₁ preferentially responds to LTD₄, while CysLT₂ responds to both LTC₄ and LTD₄. These receptors engage Gi/o and/or Gq/11 pathways, depending on the subtype and cellular context, to regulate calcium mobilization, cell migration, and contraction. BLT₁ is prominent on leukocytes, particularly neutrophils, where it drives inflammatory cell recruitment, while BLT₂ has a broader distribution that includes epithelial cells. Cysteinyl leukotriene receptors are expressed in airway smooth muscle, immune cells, and vascular cells and contribute to bronchoconstriction, inflammation, and increased vascular permeability. Agonist-induced phosphorylation, desensitization, and internalization regulate receptor responsiveness, with mechanisms varying between subtypes. The selective CysLT₁ antagonists montelukast, zafirlukast, and pranlukast are clinically used for asthma, with availability and additional indications varying by country. No BLT₁-, BLT₂-, or CysLT₂-selective drug is currently approved for therapeutic use.