Interaction of lectins with Cryptosporidium parvum.

Cell surface carbohydrates from four clinical isolates of Cryptosporidium parvum were analyzed by agglutination assays using a battery of 20 highly purified lectins with affinity for receptor molecules containing N-acetyl-D-glucosamine (GlcNAc), N-acetyl-D-galactosamine, galactose, mannose, glucose, fucose, and N-acetyl-neuraminic acid. Tomentine, a lectin from the green seaweed Codium tomentosum, and UEA-II lectin, from Ulex europeus, both of them GlcNAc-specific lectins, agglutinated the oocysts. Subsequent inhibition assay confirmed the presence of this sugar on the surface of Cryptosporidium parvum oocysts. Codium fragile lectin, from another green seaweed, also exhibited agglutination activity against the oocysts. This is the first published demonstration of such an interaction between a human coccidian and lectins from seaweeds.