Abstract
Fibronectin is a major adhesive and opsonic glycoprotein found in plasma and tissue. Because this molecule appears to mediate a number of interactions between cells and extracellular matrix, and because the natural killer (NK) cell-tumor cell interaction results in NK cell-mediated cytotoxicity, we evaluated fibronectin in the NK cell-target cell (K 562) interaction. Fibronectin promoted dosedependent inhibition of NK cell-mediated cytotoxicity by 51Cr release assays and single cell level assays in agar gel. This inhibitory effect was demonstrated in only fibronectin-treated target cells, and fibronectin did not inhibit the formation of NK cell-target cell conjugates. Thus, fibronection should bind to target cells, and augmented the insusceptibility of target cells to cytotoxic reaction of NK cells.
