title: Identification of a sporozoite-specific antigen from Toxoplasma gondii.
abstract: Reduction of risk for human and food animal infection with Toxoplasma gondii is hampered by the lack of epidemiological data documenting the predominant routes of infection (oocyst vs. tissue cyst consumption) in horizontally transmitted toxoplasmosis. Existing serological assays can determine previous exposure to the parasite, but not the route of infection. We have used difference gel electrophoresis, in combination with tandem mass spectroscopy and Western blot, to identify a sporozoite-specific protein (T. gondii embryogenesis-related protein [TgERP]), which elicited antibody and differentiated oocyst- versus tissue cyst-induced infection in pigs and mice. The recombinant protein was selected from a cDNA library constructed from T. gondii sporozoites; this protein was used in Western blots and probed with sera from T. gondii -infected humans. Serum antibody to TgERP was detected in humans within 6-8 mo of initial oocyst-acquired infection. Of 163 individuals in the acute stage of infection (anti- T. gondii IgM detected in sera, or < 30 in the IgG avidity test), 103 (63.2%) had detectable antibodies that reacted with TgERP. Of 176 individuals with unknown infection route and in the chronic stage of infection (no anti- T. gondii IgM detected in sera, or > 30 in the IgG avidity test), antibody to TgERP was detected in 31 (17.6%). None of the 132 uninfected individuals tested had detectable antibody to TgERP. These data suggest that TgERP may be useful in detecting exposure to sporozoites in early T. gondii infection and implicates oocysts as the agent of infection.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Beltsville, Maryland 20705, USA. dolores.hill@ars.usda.gov
authors.forename: Dolores
authors.initials: D
authors.lastname: Hill
authors.forename: Cathleen
authors.initials: C
authors.lastname: Coss
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: Kristen
authors.initials: K
authors.lastname: Wroblewski
authors.forename: Mari
authors.initials: M
authors.lastname: Sautter
authors.forename: Tiffany
authors.initials: T
authors.lastname: Hosten
authors.forename: Claudia
authors.initials: C
authors.lastname: Muñoz-Zanzi
authors.forename: Ernest
authors.initials: E
authors.lastname: Mui
authors.forename: Shawn
authors.initials: S
authors.lastname: Withers
authors.forename: Kenneth
authors.initials: K
authors.lastname: Boyer
authors.forename: Gretchen
authors.initials: G
authors.lastname: Hermes
authors.forename: Jessica
authors.initials: J
authors.lastname: Coyne
authors.forename: Frank
authors.initials: F
authors.lastname: Jagdis
authors.forename: Andrew
authors.initials: A
authors.lastname: Burnett
authors.forename: Patrick
authors.initials: P
authors.lastname: McLeod
authors.forename: Holmes
authors.initials: H
authors.lastname: Morton
authors.forename: Donna
authors.initials: D
authors.lastname: Robinson
authors.forename: Rima
authors.initials: R
authors.lastname: McLeod
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis* / Q000097:blood; D000953:Antigens, Protozoan / Q000032:analysis* / Q000276:immunology; D015153:Blotting, Western; D001921:Brain / Q000469:parasitology; D002415:Cats; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D008297:Male; D008460:Meat / Q000469:parasitology; D051379:Mice; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000175:diagnosis / Q000209:etiology / Q000276:immunology; D015800:Protozoan Proteins / Q000032:analysis* / Q000276:immunology; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology / Q000635:transmission; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis / Q000209:etiology* / Q000635:transmission; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins