Effect of the Removal of Cell Surface Sialic Acids on Cell Aggregation in vitro

Abstract

THE extensive investigations of Gottschalk¹ and Warren² have established that sialic acids (9-carbon sugars) occur widely in all orders of the Vertebrata. In many species histochemical studies using both the light and the electron microscope have shown that these acids constitute part of a carbohydrate-rich substance found at the surfaces of both normal^3,4 and tumour cells^5,6. The utilization of the specific enzyme N-acetylneuraminate glycohydrolase¹⁵ has enabled investigators to demonstrate by microchemical tests that sialic acids occur at the surfaces of Ehrlich ascites tumour cells^7,8, of red blood cells^9,10 and of normal and malignant rat liver cells¹¹. Studies employing cell electrophoresis have resulted in the detection of sialic acids in many other cell types¹², and have demonstrated that the increased negative mobilities of some transformed cell lines¹³ and of RPMI No. 41 cells (derived from human osteogenic sarcoma) in mitotic peak phase¹⁴ are caused by an increased amount of cell surface sialic acids.