A cell-binding, immunoglobulin-like protein from human plasma. II. Cell-binding activity.

Cell adhesion to plastic surfaces coated with a new high-molecular-mass immunoglobulin-like protein from normal human plasma was studied. Mouse subdermal fibroblasts, hamster kidney cells, human umbilical vein endothelial cells, and human skin fibroblasts were found to become attached to the surface, but cancer cells derived from human stomach cancer and human breast cancer did not. The appearance of the attached cells differed from that of cells attached to surfaces coated with fibronectin or concanavalin A. The cell adhesion to the surfaces coated with the protein was inhibited by goat anti-human IgM. Furthermore, the binding of the protein to the cell surfaces was demonstrated by the indirect immunofluorescence method. It is concluded that this protein is a new cell-binding protein.