Isolation of a collagen-dependent cell attachment factor

MOST untransformed mammalian cells require an appropriate surface for survival and growth in vitro; this phenomenon has been termed anchorage dependence1. Glass, tissue culture plastics, fibrin clots and collagen surfaces have long been recognised as substrates able to support the attachment and growth of cells. Since the cell plasma membrane is separated from plastics substrates by a 450 A layer of electron opaque material2, the nature of the 450 A would appear to be more important in cell attachment than the chemical composition of the plastic. It is demonstrated here that cell attachment to collagen is mediated by a high molecular weight protein present in serum.