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.

Beit Memorial Research Fellow.