ADSORPTION CHARACTERISTICS OF PLASMA FIBRONECTIN IN RELATIONSHIP TO BIOLOGICAL-ACTIVITY

Fibronectins are a group of glycoproteins found in plasma and other body fluids and bound to the surface of many different types of cells. A variety of evidence suggests that plasma fibronectin (pFN) may play an important role in hemostasis. The authors studied the adsorption properties of plasma fibronectin (pFN) on wettable tissue culture (TC) dishes and nonwettable bacteriological (BAC-T) dishes in relationship to its biological activity of promoting fibroblast spreading. The binding of pFN to the dish surfaces was found to be very tight and partially resistant to treatments with 1M NaOH, 2% SDS, 8M urea, or 6M guanidine HCl. Only the combination of trypsin (1 mg/ml) followed by 1M NaOH resulted in complete recovery of surface bound material. The amount of surface bound pFN did not directly correlate with its activity when comparing TC and BAC-T dishes. At low concentrations, more pFN adsorbed onto the surfaces of BAC-T dishes than TC dishes, but the adsorbed material was biologically less active on BAC-T dishes. At high concentrations, pFN adsorbed similarly on both dish surfaces reaching a maximum level of 320 ng/cm**2 or 4. 4 multiplied by 10**1**1 molecules/cm**2.