Example: Interaction between an epithelial cell and a leukocyte

1. During an inflamatory response, epithelial cells convert arachidonic acid to 15-hydroxyarachidonic acid. (The arachidonic acid is prodced via phospholipase A2).
2. 15-hydroxyarachidonic acid is transferred to interacting leukocytes, which convert it to lipoxins. (During an inflammatory response, 5-lipoxygenase is associated with FLAP and is active).
3. Lipoxins are produced and secreted into the blood