Cellular sialoglycoconjugates: a histochemical perspective

Sialic acids are found at the non-reducing terminus of oligosaccharide side-chains of most glycoproteins and glycolipids. Their expression is often developmentally regulated during organogenesis and in differentiating cells. Further, differential expression of various sialyltransferases results in organ- and cell-type specific expression of sialylated glycosylation sequences. The availability of highly specific lectins and of monoclonal antibodies has permitted histochemical investigations of the various cellular and subcellular aspects of the process of sialylation. This review provides a survey on the developmentally regulated and organ- as well as cell-type specific expression of various sialoglycoconjugates and their tumour-associated occurrence with special reference to intestine and kidney.