Printed in Great Britain © Company of Biologists Limited igSo ROLE OF CELL SURFACE RECEPTOR MOBILITY IN CONCANAVALIN A-INDUCED AGGLUTINATION OF NOVIKOFF HEPATOMA AND NORMAL RAT LIVER CELLS

The relationship between Con A-receptor mobility and Con A-induced agglutination of Novikoff hepatoma and normal rat liver cells was investigated. Novikoff cells, incubated with fluorescein-labelled Con A at 3 °C displayed uniform, ring-like surface fluorescence. Increasing the temperature of the cells to 37 °C caused capping of Con A receptors in approximately 65 % of the cells, a phenomenon that could be prevented by prefixing the cells with glutaraldehyde. In spite of these variations in Con A-receptor distribution, Con A-induced agglutination was remarkably constant over a temperature range from 3 to 37 °C. In contrast to NovikofF cells, normal hepatocytes displayed a uniform, ringlike surface fluorescence at both 3 and 37 °C. No capping was observed. However, hepatocytes, similar to Novikoff cells, were agglutinable by low concentrations of Con A. These findings indicate that, in this model system, Con A-induced cytoagglutination is not dependent upon long-range lateral mobility of Con A receptors. The qualitative differences in the lateral mobility of cell-surface Con A leceptors of normal and malignant rat liver cells may represent a marker for neoplastic transformation during hepato-carcinogenesis, adaptation to growth in ascitic form, or progression of a tumour to a more malignant state