title: Detection of Clonorchis sinensis circulating antigen in sera from Chinese patients by immunomagnetic bead ELISA based on IgY.
abstract: BACKGROUND
  Clonorchiasis, caused by Clonorchis sinensis, is widely distributed in Southeast Asia including China. Clonorchiasis is included in control programs of neglected tropical diseases by World Health Organization (WHO) because it is one of the major health problems in most endemic areas. Diagnosis of clonorchiasis plays a key role in the control programs. However, so far, there is no satisfactory method for clonorchiasis because of low sensitivity, poor practicality and high false positivity of available diagnostic tools.
  
  
  RESULTS
  We developed an immunomagnetic bead enzyme-linked immunosorbent assay (ELISA) based on IgY (egg yolk immunoglobulin) against cysteine proteinase of C. sinensis for detection of circulating antigen in serum samples of patients infected with C. sinensis. The polyclonal IgY, coated with magnetic beads, was used as a capture antibody and a monoclonal IgG labeled with horseradish peroxidase as a detection antibody in the IgY-based immunomagnetic bead ELISA system (IgY-IMB-ELISA). The results showed that the sensitivity of IgY-IMB-ELISA was 93.3% (14 of 15) in cases of heavy infection (5000 to 9999 eggs per gram feces, i.e, EPG 5000-9999), 86.7% (13 of 15) in cases of moderate infection (EPG 1000-4999) and 75.0% (9 of 12) in cases of light infection (EPG <1000) of clonorchiasis. Together 36 of total 42 (85.7%) serum samples of human clonorchiasis gave a positive reaction. There was a significant correlation between ELISA optical density and egg counts (EPG) with a correlation coefficient of 0.83 in total 42 patients. There were no positive results in patients with trichinosis (n = 10) or cysticercosis (n = 10). Cross-reactivity was 6.7% (2 of 30) with schistosomiasis japonica and 10.0% (3 of 30) with paragonimiasis, respectively. No positive reaction was found in 20 healthy persons.
  
  
  CONCLUSIONS
  Our findings suggest that IgY-IMB-ELISA appears to be a sensitive and specific assay for detection of circulating antigen in human clonorchiasis.
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Nie
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Shengjun
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yonglong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Jiahui
authors.initials: J
authors.lastname: Lei
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D000947:Antigens, Helminth / Q000097:blood* / Q000302:isolation & purification; D002681:China; D003003:Clonorchiasis / Q000097:blood* / Q000469:parasitology / Q000473:pathology; D003004:Clonorchis sinensis / Q000276:immunology / Q000302:isolation & purification* / Q000472:pathogenicity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; C016512:IgY; D007136:Immunoglobulins