The structure of the influenza virus neuraminidases, the spatial organization of their active site, the mechanism of carbohydrate chains desialylation by neuraminidase, and its role in the influenza virus function at different stages of the viral infectious cycle are considered in this review. Data on the neuraminidase substrate specificity and different approaches in studying the activity of this enzyme are summarized. In addition, data on neuraminidase inhibitors (as antivirals) are provided, along with considerations on the mechanisms of resistance of modern influenza viruses to those antivirals.

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Several types of polymeric glycoconjugates, N-substituted polyacrylamides, have been synthesized by the reaction of activated polymers with omega-aminoalkylglycosides: (i) (carbohydrate-spacer)n-polyacrylamide, 'pseudopolysaccharides'; (ii) (carbohydrate-spacer)n-phosphatidylethanolaminem-polyacrylamide, neoglycolipids, derivatives of phosphatidylethanolamine; (iii) (carbohydrate-spacer)n-biotin-polyacrylamide, biotinylated probes; (iv) (carbohydrate-spacer)n-polyacrylamide-(macroporous glass), affinity sorbents based on macroporous glass, covalently coated with polyacrylamide. An almost quantitative yield in the conjunction reaction makes it possible to insert in the conjugate a predetermined quantity of the ligand(s). Pseudopolysaccharides proved to be a suitable form of antigen for activation of polystyrene and poly(vinyl chloride) plates (ELISA) and nitrocellulose membranes (dot blot), being advantageous over traditional neoglycoproteins. Polyvalent glycolipids insert well in biological membranes: their physical properties, particularly solubility, can be changed in a desired direction. Biotinylated derivatives were used as probes for detection and analysis of lectins.

Anomeric aminobenzylglycosides of Neu5Ac were coupled with the polyacrylate carrier and a number of synthetic polyvalent sialosides obtained were investigated as inhibitors of influenza virus attachment. The inhibitory activity of polymeric sialosides is highly dependent upon the Neu5Ac residue content and the nature of the carrier. The polyacrylic acid based polymer bearing 10 mol% of Neu5Ac is 3 orders of magnitude more potent inhibitor than the corresponding monovalent benzylsialoside and considerably more active than fetuin.