No abstract

Landschutz ascites tumour cells treated in vitro withIn recent years the concept " cell periphery " has been enlarged to include an outer zone or " fuzzy layer ", consisting in the main of a carbohydrate-protein gel largely composed of mucopolysaccharide and glycoprotein. This outer layer is now known to be the site of immunologically specific reactions and to be intimately connected with certain behavioural characteristics of isolated cells, such as electrophoretic mobility, cellto-cell adhesiveness and adherence to glass. The subject has been comprehensively reviewed by Weiss (1967). Since many of the properties just referred to are altered in malignancy (Abercrombie and Ambrose, 1962;Weiss, 1967), recent research has emphasized the importance of the peripheral regions of the cell and the factors affecting it.The electrophoretic mobility of isolated cells is determined by the density of their negative surface charges, Exposure of cells to enzyme preparations such as neuraminidase or various non-specific proteolytic enzymes such as trypsin produces alterations in surface components and, therefore, in electrophoretic behaviour. From this type of approach it has been deduced that glycoproteins containing N-acetylneuraminic acid (sialic acid)