On the mechanism of the increased aggregation by neuraminidase of 16 c malignant rat dermal fibroblasts in vitro

The aggregation of briefly trypsinized 16 C malignant rat dermal fibroblasts as measured by gyratory shaker/electronic particle counting technique is increased by neuraminidase. Enzyme treatment also exposes soybean and Ricinus communis agglutinin-binding sites as judged by cell agglutination. Desialysed bovine submaxillary mucin and desialysed, agalacto fetuin reversed the neuraminidase-stimulated increase in aggregation, whereas desialysed fetuin and ovalbumin did not. The effective glycoproteins also acted as acceptors in cellular sialyl- and galactosyl-transferase reactions, and these activities are detected in plasma membrane fractions. The possibility that neuraminidase increases cellular aggregation by generating acceptor sites for interaction with cell surface glycosyltransferases, is discussed.