title: Receptor/ligand interactions between Cryptosporidium parvum and the surface of the host cell.
abstract: The ability of membrane antigens on sporozoites of the intestinal pathogen, Cryptosporidium parvum, to bind host cell surface antigens was investigated. A novel membrane-associated protein of approximately 47 kDa, designated CP47, was found to possess significant binding affinity for the surface of both human and animal ileal cells. This protein was purified by a combination of anion-exchange chromatography on FPLC and immunoaffinity chromatography. Purified CP47 demonstrated competitive binding with parasite-associated membrane antigens to membranes of HCT-8 and ileal cells in a dose-dependent manner. Furthermore, the binding activity of CP47 was found to be Mn2+-sensitive, and was completely inhibited in the presence of 10 mM MnCl2. These results were consistent with earlier findings demonstrating the inhibitory effect of Mn2+ ions on Cryptosporidium infection both in vitro and in vivo (Nesterenko et al., Biol. Trace Elem. Res. 56 (1997) 243-253). Immunoelectron microscopy using gold-conjugated antibodies revealed CP47 to be localized at the apical end of the sporozoites. A single protein with an electrophoretic mobility of 57 kDa was purified from host cell membranes using CP47-Affigel. Similarly, affinity purification of this protein was abrogated in the presence of Mn2+. These data suggest that a novel parasite protein, CP47, may play an important role in sporozoite/host cell attachment.
authors.affiliation: Division of Biology, Ackert Hall, Kansas State University, Manhattan, KS 66506, USA. mvn@ksu.edu
authors.forename: M V
authors.initials: MV
authors.lastname: Nesterenko
authors.forename: K
authors.initials: K
authors.lastname: Woods
authors.forename: S J
authors.initials: SJ
authors.lastname: Upton
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology* / Q000302:isolation & purification; D000954:Antigens, Surface / Q000276:immunology*; D002846:Chromatography, Affinity; D003457:Cryptosporidiosis / Q000276:immunology; D016785:Cryptosporidium parvum / Q000276:immunology*; D006801:Humans; D007082:Ileum / Q000276:immunology / Q000378:metabolism; D007150:Immunohistochemistry; D008345:Manganese / Q000378:metabolism; D015800:Protozoan Proteins / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; D008345:Manganese