title: Surface binding properties of aged and fresh (recently excreted) Toxoplasma gondii oocysts.
abstract: The surfaces of aged (10 years) and fresh (recently excreted) oocysts of Toxoplasma gondii were investigated using monoclonal antibody (mAb) and lectin-binding assays. Fresh oocysts bound a wall-specific mAb labelled with fluorescein isothiocyanate while aged oocysts did not. In contrast, the walls of aged oocysts bound a lectin (wheat germ agglutinin, WGA), but not the walls of fresh oocysts. Exposure of oocysts to detergent solutions or trypsin did not affect the binding properties of the walls of the oocysts. However, exposure of fresh oocysts to acidified pepsin enabled labelling of the walls with WGA, presumably due to the relevant moieties on the oocyst walls becoming exposed. WGA binding, but not mAb binding, was partially abrogated with periodate exposure. These findings reveal a significant difference in the binding properties of oocyst walls from "aged" and "fresh" oocysts. The results are of relevance when considering technologies for isolating or detecting T. gondii oocysts in environmental samples based on oocyst surface properties, as used for other protozoan parasites. Our results suggest the possibility of developing a WGA-based separation procedure for isolating Toxoplasma oocysts from environmental matrices, in which pepsin pre-treatment would be included to ensure that both fresh and aged oocysts were isolated.
authors.affiliation: Parasitology Laboratory, Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
authors.forename: Jemere Bekele
authors.initials: JB
authors.lastname: Harito
authors.affiliation: Alere A.S., Oslo, Norway.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Campbell
authors.affiliation: Norwegian Kennel Club and Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, Department of Companion Animal Clinical Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
authors.forename: Kristin W
authors.initials: KW
authors.lastname: Prestrud
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, BARC-East, Beltsville, MD 20705-2350, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.affiliation: Parasitology Laboratory, Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway. Electronic address: lucy.robertson@nmbu.no.
authors.forename: Lucy J
authors.initials: LJ
authors.lastname: Robertson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D002415:Cats; D005589:Foxes; D037102:Lectins / Q000378:metabolism*; D033661:Oocysts / Q000187:drug effects / Q000378:metabolism; D010434:Pepsin A / Q000494:pharmacology; D010504:Periodic Acid / Q000494:pharmacology; D013499:Surface Properties; D013552:Swine; D013997:Time Factors; D014122:Toxoplasma / Q000187:drug effects / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014909:Wheat Germ Agglutinins / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D037102:Lectins; D014909:Wheat Germ Agglutinins; D010504:Periodic Acid; C009288:metaperiodate; D014357:Trypsin; D010434:Pepsin A
keywords: Binding; Lectin; Oocyst; Pepsin; Surface; Toxoplasma; Walls; Wheat germ agglutinin