Electrophoretic characterization of Cryptosporidium parvum (KSU-1 isolate) (Apicomplexa: Cryptosporidiidae)

Abstract

Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting, lectin binding, and iodine-125 surface labeling of sporozoites were used to probe the coccidial pathogen, Cryptosporidium parvum. Analysis of silver-stained profiles of CsCl gradient purified, freeze–thawed oocysts revealed >50 bands, whereas profiles of anion exchange chromatography purified sporozoites displayed >40 bands. Surface iodination of sporozoites revealed about 20 surface proteins, the most heavily labeled of which had molecular masses of 18–20, 37–39, 48, 73–76, and 102–105 kilodaltons. Following electrophoresis and Western blotting, 4 of 12 different 125I-labeled lectin probes bound to blots and collectively revealed at least 19 bands to be glycosylated. Concanavalin A specifically recognized at least 14 bands, whereas Griffonia simplicifolia agglutinin I, Maclura pomifera agglutinin, and soybean agglutinin recognized 5–7 bands each. Of the five most heavily labeled surface molecules, the four with lowest molecular masses all appeared to be glycosylated. Immunoblotting with sera collected from two individuals 30 days after they passed oocysts revealed that the majority of parasite glycoproteins and surface molecules are immunogenic.