An antibody that inhibits fibronectin-independent adhesion of fibroblasts to extracellular matrix material.

Chinese hamster ovary (CHO) fibroblasts adhere to the extracellular matrix by both fibronectin-dependent and -independent mechanisms (Harper and Juliano, 1981a,b). Previous studies have suggested that a trypsin-sensitive, 265,000-dalton membrane glycoprotein (gp265) is involved in the fibronectin-independent adhesion process. Using a polyclonal antibody against soluble products obtained from trypsin-treated CHO cells, we have been able to further analyze this involvement. This antibody immunoprecipitates a trypsin-sensitive 265,000-dalton protein from detergent-solubilized cells. Incubation of AdvF11, a variant cell line that does not utilize fibronectin for adhesion, with this antibody blocks their adhesion to extracellular matrix material (ECM). The immunoglobulin fraction will also partially block adhesion of the parental cell line to ECM particularly when the ECM is first treated with an antifibronectin antibody. Taken together these results add support for the involvement of gp265 in fibronectin-independent adhesion and provide a methodology for further characterization.