title: Diagnostic value of recombinant Tp0821 protein in serodiagnosis for syphilis.
abstract: Syphilis is a multistage sexually transmitted disease that remains a serious public health concern worldwide. The coexistence of Treponema pallidum with other closely related members of spirochaeta, such as Leptospira spp. and Borrelia burgdorferi, has complicated the serodiagnosis due to cross-reactive antigens. In this study, recombinant Tp0821 protein was expressed in Escherichia coli and purified by metal affinity chromatography. Then enzyme-linked immunosorbent assays (ELISAs) based on Tp0821 for the detection of specific antibodies were established. The relative positive rates of the IgM ELISA and the IgG ELISA were found to be 91·0 and 98·3%, respectively, when screening 578 syphilis specimens. The specificities were 94·3 and 100%, respectively, when cross-checking with serum samples obtained from 30 patients with Lyme disease, five patients with leptospirosis, and 52 uninfected controls. In addition, relative positive rates and specificities of Tp0821 for human sera were all 100% in Western blotting. When compared to the syphilis diagnostic tests commonly used in clinical settings, we found that the results of Tp0821-based ELISAs correlated well with the results of the treponemal tests, specifically the T. pallidum particle agglutination (TP-PA) test and the chemiluminescent immunoassay (CIA). Thus, these findings identify Tp0821 as a novel serodiagnostic candidate for syphilis.
  
  
  CONCLUSIONS
  In this study, we expressed and purified the Treponema pallidum protein Tp0821 and developed Tp0821-based enzyme-linked immunosorbent assays (ELISAs) for the detection of specific antibodies. The serodiagnostic performance of the recombinant protein was then evaluated. When compared to the results of syphilis diagnostic tests commonly used in clinical settings, we found that the reactivities of syphilitic sera with the recombinant antigen correlated well with the results of the treponemal tests, specifically the T. pallidum particle agglutination (TP-PA) test and the chemiluminescent immunoassay (CIA). Thus, the recombinant protein shows promise as a new diagnostic antigen in the ELISAs.
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: Y
authors: Y
authors: Xie
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: M
authors: M
authors: Xu
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: C
authors: C
authors: Wang
authors: Clinical Laboratory Department, Hunan Provincial People's Hospital, Changsha, Hunan, China.
authors: J
authors: J
authors: Xiao
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.|Clinical Laboratory Department, The Second Affiliated Hospital of University of South China, Hengyang, Hunan, China.
authors: Y
authors: Y
authors: Xiao
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: C
authors: C
authors: Jiang
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: X
authors: X
authors: You
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: F
authors: F
authors: Zhao
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: T
authors: T
authors: Zeng
authors: Clinical Laboratory Department, The First Affiliated Hospital of University of South China, Hengyang, Hunan, China.
authors: S
authors: S
authors: Liu
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: X
authors: X
authors: Kuang
authors: Institution of Pathogenic Biology, Medical College, University of South China, Hengyang, Hunan, China.|Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan, China.|Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan, China.
authors: Y
authors: Y
authors: Wu
mesh_terms: D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology*; D008875:Middle Aged; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology*; D012680:Sensitivity and Specificity; D013587:Syphilis / Q000175:diagnosis* / Q000382:microbiology; D013588:Syphilis Serodiagnosis / Q000379:methods*; D014210:Treponema pallidum / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; C496546:Tp32 protein, Treponema pallidum
keywords: ELISA; Tp0821; Treponema pallidum; recombinant antigen; serodiagnostic candidate; syphilis