Cell surface molecules involved in fibronectin-mediated adhesion. A study using specific antisera

Attachment and spreading of baby hamster kidney (BHK) fibroblasts to fibronectin-coated surfaces can be inhibited by antibodies, and the (Fab)2 fragments, prepared against the cells. The antibodies reacted specifically with ricin-binding glycoproteins of the cell surface, the major components having molecular weights of 130-140 K. The antibodies reacted also with mouse fibroblasts (L-cells) and Chinese hamster ovary (CHO)-cells and inhibited their fibronectin-mediated adhesion to inert surfaces. Antisera raised against material isolated from the underside of BHK cells spread out on fibronectin-coated substrata using a cleavable, photolabile heterobifunctional cross-linking reagent also affected the interactions of cells with fibronectin-coated surfaces. The antibodies stained the peripheray of BHK cells and L-cells in a discontinuous periodic manner and immunoprecipitated as a major component a low molecular weight (approximately 47 K) glycoprotein from cell extracts. These results indicate that different specific antisera modify cell-substratum adhesion, probably by interacting with different cell surface components. The properties of multiple factors involved in the attachment and spreading of cells to suitably adhesive substrata are discussed.