LIPOXIN B4

Lipoxins are a series of anti-inflammatory lipid mediators whose brief appearance generally signals the resolution of inflammation. Lipoxin A4 (LXA4) is a potent inhibitor of leukotriene (LT)-triggered polymorphonuclear neutrophil (PMN)-endothelial cell interaction and also blocks PMN migration stimulated by LTB4. LXB4 is a positional isomer of LXA4 produced by the metabolism of 15-HETE or 15-HpETE by human leukocytes. At a concentration of 10-7 M, LXB4 inhibits PMN migration stimulated by LTB4 and inhibits LTB4-induced adhesion of PMNs with an IC50 value of ~3 X 10-10 M.