Basement Membrane Glycoprotein Laminin Is an Agglutinin1

Abstract

Laminin was purified to homogeneity from the extracellular matrix and soluble fraction of teratocarcinoma OTT6050 and also partially purified from the ascitic fluid of the mice carrying the teratocarcinoma. These laminin preparations were found to agglutinate trypsinized, glutaraldehyde-fixed rabbit erythrocytes. The hemagglutinating activity was inhibited by porcine gastric mucin, while invertase and mannan were not inhibitory. Hepann and heparan sulfate also inhibited the hemagglutination. Simple sacchandes such as D-galactose, N-acetyl D-glucosamine, and N-acetyl D-galactosamine were not inhibitory, but D-glucosamine and D-galac-tosamine were. The hemagglutinating activity required Ca²₊ and was dependent upon temperature. These results raised the possibility that laminin functions also in cell-cell interactions such as cell-cell adhesion. In addition, we report that laminin synthesized by the teratocarcinoma did not carry the large carbohydrate chain characteristic of early embryonic cells.