MIGRATORY FUNCTIONS OF NATURAL-KILLER-CELLS

In numerous investigations it has been found that natural killer (NK) cells are among the cells arriving early at the site of defense. To re ach the tissue sites of defense, the circulating NK cells have to pene trate through the capillary wall and actively migrate along the matrix proteins towards the tumor or infected target cells. For this process NK cells need adhesion receptors which do not anchor them but allow r eversible binding. The migration capacity of NK cells is found to be h igher than that of other lymphocytes. NK cells also have the ability t o increase rapidly the migratory response. IL-2 and a peptide derived from ICAM-2 are potential inducers of NK cell migration. ICAM-2 is exp ressed on endothelium, a site where lymphocytes start migration. Also, a matrix protein, fibronectin, increases NK cell migration. This revi ew focuses on the migratory capacity of NK cells and on the receptors which NK cells use when they migrate on different substrata.