Abstract
The gut-associated excretory antigen CAA (circulating anodic antigen) from adult Schistosoma mansoni worms was isolated by immunoaffinity chromatography. Amino acid analysis following alkaline borohydride treatment indicated that CAA is a glycoprotein, O-glycosylated at Thr. The primary structure of the released O-glycan moiety was investigated by one- and two- dimensional, homo- and heteronuclear 1H and 13C NMR spectroscopy. It was found that the major carbohydrate chains have a novel polysaccharide structure, consisting of a branched disaccharide repeating unit containing 2- acetamido-2-deoxy-β-D-galactopyranose (β-D-GalpNAc) and β-D- glucopyranuronic acid (β-D-GlcpA). (→6)-β-D-GalpNAc-(1→)(n)3↑1β-D- GlcpA. The major antigenic character of CAA arises from this novel polysaccharide, which was shown to be an absolutely specific diagnostic marker in schistosomiasis. The cross-reactivity of CAA with anti-CCA (circulating cathodic antigen) monoclonal antibodies is caused by the presence of a small amount of O-linked CCA-poly-Lewis x carbohydrate chains on the CAA protein chain.
Original language | English |
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Pages (from-to) | 31510-31517 |
Number of pages | 8 |
Journal | Journal of Biological Chemistry |
Volume | 269 |
Issue number | 50 |
Publication status | Published - 12 Jul 1994 |
Keywords
- antigen
- polysaccharide
- antigen detection
- article
- carbohydrate analysis
- carbon nuclear magnetic resonance
- immunogenicity
- nonhuman
- priority journal
- proton nuclear magnetic resonance
- Schistosoma mansoni
- schistosomiasis
- structure analysis