SCHISTOSOMA-MANSONI - FRACTIONATION AND CHARACTERIZATION OF THE GLYCOCALYX AND GLYCOGEN-LIKE MATERIAL FROM CERCARIAE

The glycocalyx (GCX) that covers schistosomal cercariae is a complex m olecule that has immunomodulating properties. Here, we purified millig ram amounts of GCX using Anguilla lectin which binds to the GCX coveri ng the cercarial body and tail. Typically, 10 million cercariae were e xtracted with phenol, dialyzed, and chromatographed on a Sepharose 2B- CL column. An average of 39 mg of total carbohydrate eluted near the v oid volume from which 31 mg of glycogen-like material was further sepa rated by lectin affinity chromatography. Its identity was established by compositional analysis, sensitivity to amylase digestion, and its n uclear magnetic resonance spectrum. The lectin-bound GCX was eluted wi th 0.1M fucose with a final yield of 5.3 mg carbohydrate. Fucose compo sed 40% of the total GCX carbohydrate with lesser but approximately eq ual amounts of galactose, glucosamine, and galactosamine present. NMR data indicated that the amino sugars were N-acetylated. Glucose was al so present but in varying amounts in different preparations of GCX. Ol igosaccharides were released from GCX by hydrazinolysis and separated by electrophoresis after reductive amination to 8-aminonaphthalene-1,3 ,6-trisulfonic acid (ANTS). Bands comigrating with standards containin g 11, 12, 16, and 17 sugar residues were detected. Thus, the GCX is a complex structure composed of oligosaccharides, probably linked to a p eptide. (C) 1994 Academic Press, Inc.