The role of N-linked carbohydrates in the antigenicity of Taenia solium metacestode glycoproteins of 12, 16 and 18 kD

The glycoproteins of 12-28 kD from Taenia solium metacestodes provide a hig h specificity and sensitivity for the serological diagnosis of the central nervous system infection, neurocysticercosis. Their widespread use as antig ens for routine serological assays will require their production in large a nd reproducible amounts. Prior to determining the ideal strategy to produce these antigens at a large scale, it is important to determine the contribu tion of the carbohydrates to the antigenicity of these molecules, given the uncertainty of reproducing saccharidic epitopes in recombinant expression systems. In this study we examined this issue. The chemical oxidation of th e carbohydrates of the 12-28 kD glycoproteins with sodium metaperiodate, re duced the antigenicity of the molecules to variable extents, with the more notable changes being detected for the 18 and 28 kD antigens. This approach was complemented by purification of the 12, 16 and 18 kD antigens, followe d by the enzymatic deglycosylation of their abundant N-linked oligosacchari des, Silver-stained SDS-PAGE analysis indicated that the three deglycosylat ed antigens now migrated as 7 kD products, suggesting a protein backbone wi th a similar size, but different extents of glycosylation. By Western blot, the antigenicity of these antigens was diminished. This was more notable f or the 18 kD antigen, which is more heavily glycosylated than the 12 or 16 kD glycoproteins, These data suggest that the antigenicity of the glycoprot eins of T. solium is due to a combination of carbohydrate and protein epito pes. (C) 2001 Elsevier Science B.V. All rights reserved.