Enzyme-linked immunosorbent assay to quantify fibronectin.

Fibronectin, a multifunctional soluble glycoprotein, is found in soluble form in blood and other body fluids. Fibronectin binds to biological substrata--collagen, gelatin, etc.--and to nonbiological substrata as well. An interesting finding was that fibronectin bound to polystyrene plastic quickly and tightly and further treatment of plastic with denaturing agents did not remove or denature it once it was adsorbed. Through the use of this property, a three-step noncompetitive enzyme-linked immunosorbent assay has been developed to quantify soluble fibronectin in biological samples. The following parameters were studied: selective attachment of fibronectin to polystyrene; interference caused by increasing amounts of external protein; and linear response and limit of sensitivity. The procedure has been applied to measure fibronectin from different animal sources.