Schistosoma mansoni: fractionation of polysaccharide egg antigens by lectin affinity chromatography

Crude polysaccharide antigen was extracted from Schistosoma mansoni egg homogenate by 44% aqueous phenol. The aqueous soluble polysaccharide extract was subjected to affinity chromatography with concanavalin A-Sepharose 4B. Two fractions (bound and unbound) were obtained; both of them gave precipitin lines with serum obtained from mice infected with S. mansoni. These precipitin lines gave partial identity. Further fractionation with wheat germ agglutinin-sepharose of the unbound fraction resulted in three antigenic fractions. These different antigens were eluted with different N-acetylglucosamine molarities (0, 0.05) and 0.5) and gave lines of identity when reacted against infected mouse serum. When the four antigenic materials were subjected to polyacrylamide gel electrophoresis and stained for proteins and polysaccharides no migration bands were observed. The chemical analysis of the two initial fractions showed a small percentage of amino acids in both fractions. Sugar analysis with gas-liquid chromatography showed different sugar composition of the two initial fractions.