Studies on the mechanism of cell attachment to a substratum: Evidence for three biochemically distinct processes

Experiments are reported which indicate that initial cell contact to a substratum and cell attachment to that substratum are biochemically distinct phenomena. Furthermore, cell attachment in the presence of fetal calf serum in the incubation medium (serum dependent) is dissimilar to cell attachment in the absence of serum in the incubation medium (serum independent). The cell contact process was inhibited both by osmotic shock of the cells and by low temperature, but was unaffected by treatment of the cells with trypsin, N-ethylmaleimide (NEM), or glutaraldehyde. Serum-dependent attachment was inhibited by osmotic shock of cells or by treatment of the cells with trypsin, NEM, or glutaraldehyde, but was unaffected by low temperature. Serum-independent attachment was unaffected by any of the above conditions.