Bacterial Neuraminidase and Altered Immunological Behavior of Treated Mammalian Cells

Abstract

Publisher Summary This chapter discusses the bacterial neuraminidase and altered immunological behavior of treated mammalian cells. The enzyme neuraminidase is widely available in a large variety of bacteria and viruses. It is also present in various animal tissues, cells, and body fluids. The substrate of the enzyme is sialic acid-a 9-carbon sugar that is an important constituent of mammalian cell-surface glycoproteins and glycolipids. The occurrence of neuraminidase in bacteria and viruses has been shown to have some relevance to the infectivity and pathogenicity of various microbes. Neuraminidase from various sources differs in substrate specificity. The most reactive one is Vibrio cholerae neuraminidase (VCN)—the enzyme that can hydrolyze 2, 3-, 2, 6-, and 2,8-α-glycosidic linkages between the sialic acid and carbohydrate of the glycoproteins. Although almost all mammalian cells contain sialic acid, it is found in more abundant quantities on malignant cells. Treatment of cells with VCN is associated with the exposure of some hidden or crippled cell-surface antigens, which are otherwise not available on the untreated cell surfaces.