title: Evaluation of recombinant granule antigens GRA1 and GRA7 for serodiagnosis of Toxoplasma gondii infection in dogs.
abstract: BACKGROUND
  Toxoplasmosis, caused by the obligate intracellular parasite Toxoplasma gondii, is an important zoonotic disease worldwide. The precise detection of T. gondii infection in dogs has important public health significance. In this study, recombinant granule antigen proteins GRA1 and GRA7 were evaluated as potential diagnostic markers for T. gondii infection in dogs by an indirect enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  GRA1 and GRA7 were cloned and expressed in Escherichia coli, and the recombinant GRA1, GRA7- and Toxoplasma lysate antigen (TLA)-based ELISAs were developed and evaluated using the canine positive and negative serum samples for anti-T. gondii antibodies determined by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT), showing a seroprevalence of 15.1% by TLA- and GRA1-ELISA, and 15.8% by GRA7-ELISA, and no significant difference was observed (P > 0.05). When compared with the two reference assays, MAT and IFAT, the GRA7-ELISA showed the highest co-positivity and co-negativity rates. Receiver operating characteristic (ROC) analysis revealed a largest area under curve (AUC) of 0.973 (95% CI, 0.955 to 0.991), and a highest relative sensitivity (93.2%) and specificity (94.0%) for a cut-off value of 0.809 in GRA7-ELISA.
  
  
  CONCLUSIONS
  The results of the present study showed that GRA7-ELISA is highly sensitive and specific, and GRA7 is a potential serodiagnostic marker for the detection of T. gondii infection in dogs.
authors.forename: Zedong
authors.initials: Z
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Ge
authors.forename: Si-Yang
authors.initials: SY
authors.lastname: Huang
authors.forename: Jiping
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China. xingquanzhu1@hotmail.com.
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers; D003001:Cloning, Molecular; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology* / Q000378:metabolism; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies; D014122:Toxoplasma / Q000378:metabolism*; D014124:Toxoplasmosis, Animal / Q000175:diagnosis*
chemical_list: D000953:Antigens, Protozoan; D015415:Biomarkers; C412913:GRA1 antigen; C112573:GRA7 protein, Toxoplasma gondii; D015800:Protozoan Proteins; D011994:Recombinant Proteins