Fibronectin (cold-insoluble globulin): role in defence.

Fibronectin is a high molecular weight glycoprotein which is found in a soluble form in plasma (cold-insoluble globulin) and other body fluids and in an insoluble form in connective tissues and associated with basement membranes. Soluble fibronectin interacts with denatured collagen, heparin, fibrin, and Staphylococcus aureus, and is a substrate for thrombin, plasma and factor XIIIa. Fibronectin is thought to function as an adhesive and opsonic glycoprotein, supporting adhesion of cells including platelets, growth of connective tissue cells to fibrin clots, connective tissue formation, and in the phagocytic clearance by the reticuloendothelial system.