In situ Monitoring of In vitro Sialylation by Inclusion Bodies

Abstract

Sialic acids usually terminate oligosaccharide chains expressed on the cell surfaces and glycoproteins of vertebrates, higher invertebrates and some microorganisms. They have various important biological roles. Two of these roles, determination of anti-inflammatory activity of IgG antibodies and increasing the circulating half-life of glycoproteins and blood cells, can find application in pharmaceutical industry and medicine. For this reason, there is a need for efficient in vitro protein sialylation processes. To evaluate the efficiency of in vitro sialylation, a method for in situ monitoring in high throughput screens has been developed. It is represented by hemagglutination caused by inclusion bodies of SabA lectin. SabA lectins are proteins expressed on the cell surface of bacteria Helicobacter pylori and bind to sialic acids on the host cell surfaces. They are responsible for H. pylori mediated agglutination of erythrocytes in vitro. This presented method is fast, simple and one can avoid time-consuming purification of analyzed glycoprotein. In addition, it could provide a basic diagnostic method for determination of sialylation level of erythrocytes.