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 normal3,4 and tumour cells5,6. 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 cells7,8, of red blood cells9,10 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.