Adhesion of lymphoid cells to the carboxyl-terminal heparin-binding domains of fibronectin.

Previously, we have shown that some lymphoid cell lines adhere to fibronectin (FN)-coated substratum, whereas others do not. In this study, the adhesion of five adherent lymphoid cell lines to different FN domains was examined. These cell lines ranged in their adherence to substratum coated with FN, the cell-binding domain (CBD) fragment, or the heparin-binding domain (HBD) fragments. None of the cell lines adhered to substratum coated with the gelatin-binding domain fragment. Three of the lymphoid cell lines adhered preferentially to HBD over CBD, whereas two other lymphoid cell lines and BHK fibroblasts adhered preferentially to CBD. These results suggest that two distinct adhesive interactions occur between cells and FN and that the pattern of interaction varies among cell types. Using MOPC 315 (which adheres preferentially to HBD) as a cell model to study the cell-HBD interaction, the HBD-promoted adhesion was found to be independent of the RGD sequence and could be inhibited by anti-FN antibodies. Moreover, the MOPC 315-HBD interaction had the following characteristics: (1) adhesion was temperature dependent, (2) presence of divalent cations was necessary, (3) integrity of cellular microfilaments but not microtubules was required, (4) inhibition of protein synthesis abolished adhesion, (5) pretreatment of cells with trypsin inhibited adhesion, and (6) the adhesion was mediated by the carboxyl-terminal HBD.