Cell agglutination by a novel cell surface sialoglycopeptide inhibitor and the relationship between its protease and biological activities.

A bovine sialoglycopeptide, purified to homogeneity and capable of inhibiting cellular protein synthesis and proliferation, was shown to agglutinate a wide variety of nontransformed and transformed cells. The cell agglutination activity was shown to be independent of the biological inhibitory action and most likely related to a protease activity that could not be physically separated during purification of the sialoglycopeptide. Samples that were completely biologically inactivated retained full protease activity and their ability to agglutinate target cells. Balb/c 3T3 cells were not agglutinated by the sialoglycopeptide and they elicited a protein that interfered with the agglutination reaction and even redispursed cells that already had been aggregated by the inhibitor.