Higher organisms defend themselves against invading micro-organisms and harmful substances with their immune system. Key players of the immune system are the white blood cells (WBC), which in case of infection move in an extravasation process from blood vessels
[Wruss, Juergen; Pollheimer, Philipp D.; Meindl, Irene; Reichel, Annett; Schulze, Katrin; et al. Journal of the American Chemical Society, 2009 , vol. 131, p. 5478 - 5482]