The role of sialic acid in antigenic expression: further studies of the Landschütz ascites tumour

TLDR: The purpose of this communication is to extend studies in an attempt to define the role of sialic acid in the cell periphery as a barrier to the detection of antigens on a " non specific " transplantable tumour.

Abstract: A CARBOHYDRATE-RICH protein layer has been detected on the surface of many cell types (Rambourg and Leblond, 1967; Fawcett, 1964). Bennett (1963) compared this layer to a similar coat around protozoa and he called it the glycocalyx (\" sugar-coated \"), suggesting that it may be a universal feature of animal cells. Gasic and Beydak (1961) have drawn attention to the glycocalyx of several types of experimental tumour and demonstrated that it was rich in sialic (N-acetyl neuraminic) acid. This sialic acid is the major factor determining the net negative surface charge of many animal cell types and may well be involved in the abnormal social behaviour of tumour cells in vitro (Abercrombie and Ambrose, 1962). Furthermore, it has been postulated that the sialic acid content of the periphery of tumour cells may act in some way as a barrier to the detection of antigens by the host organism and thus help to explain the immunological paradox implicit in the growth and development of potentially antigenic tumours (Currie and Bagshawe, 1967). Studies from several laboratories have recently shown that enzymatic removal of sialic acid from the surface of some transplantable mouse tumours results in great enhancement of their immunogenicity and lend support to the \" antigen-masking\" hypothesis (Currie, 1967; Lindenmann and Klein, 1967; Sanford, 1967). The purpose of this communication is to extend these studies in an attempt to define the role of sialic acid in the cell periphery as a barrier to the detection of antigens on a \" non specific \" transplantable tumour.