Performance of novel infection phase-dependent antigens in syphilis serodiagnosis and treatment efficacy determination

Wen Liu; Meixia Deng; Xiaohong Zhang; Weiguo Yin; Tie Zhao; Tiebing Zeng; Shuangquan Liu; Yongjian Xiao; Li Zhang; Xi Luo; Feijun Zhao

doi:10.1016/j.cca.2018.10.017

Performance of novel infection phase-dependent antigens in syphilis serodiagnosis and treatment efficacy determination

Clin Chim Acta. 2019 Jan:488:13-19. doi: 10.1016/j.cca.2018.10.017. Epub 2018 Oct 13.

Authors

Wen Liu¹, Meixia Deng¹, Xiaohong Zhang², Weiguo Yin³, Tie Zhao¹, Tiebing Zeng¹, Shuangquan Liu⁴, Yongjian Xiao⁵, Li Zhang⁶, Xi Luo¹, Feijun Zhao⁷

Affiliations

¹ Pathogenic Biology Institute, Hengyang Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China.
² Pathogenic Biology Institute, Hengyang Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China; Department of Histology and Embryology, Hengyang Medical College, University of South China, Hengyang 421001, China.
³ Laboratory Department, Yuebei People's Hospital, Shaoguan 5120264, China.
⁴ Clinical Laboratory Department, The First Affiliated Hospital of the University of South China, Hengyang 421001, China.
⁵ Clinical Laboratory Department, The Second Affiliated Hospital of the University of South China, Hengyang 421001, China.
⁶ Clinical Laboratory Department, Changde Hospital of the University of South China, Changde 415000, China.
⁷ Pathogenic Biology Institute, Hengyang Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China. Electronic address: nhdxzhfj@163.com.

PMID: 30326217
DOI: 10.1016/j.cca.2018.10.017

Abstract

Objective: The objective of this study was to screen new antigens for syphilis serodiagnosis.

Methods: First, we determined whether the Treponema pallidum proteins Tp0971, Tp0768 and Tp0462 were infection phase-dependent antigens by observing serum reactivity differences in New Zealand rabbits infected with activated or inactivated T. pallidum. A non-infection phase-dependent antigen, the Tp92 membrane protein, was used as the negative control. Next, Tp0971-, Tp0768- and Tp0462-based ELISA was performed on 2138 human serum samples and compared with the T. pallidum passive particle agglutination assay (TPPA) and LiZhu™ Tp-ELISA. In addition, another 60 paired serum samples from patients at follow-up were analysed to evaluate the relationships between titre changes and differences in the A450 nm values of the Tp0971, Tp0768, Tp0462 and Tp92 antibodies measured by ELISA.

Results: Compared with Tp92 (negative control), Tp0971, Tp0768 and Tp0462 were determined to be infection phase-dependent antigens. Compared with those of the TPPA, the sensitivities of Tp0971-, Tp0768- and Tp0462-based ELISA were 96.4%, 96.9% and 93.0%, respectively, and the specificities were 97.7%, 95.4% and 98.9%, respectively, resulting in consistencies of 97.1%, 96.2% and 95.9%, respectively. Compared with those of the LiZhu™ Tp-ELISA, the consistencies of Tp0971-, Tp0768- and Tp0462-based ELISA were 95.1%, 94.2% and 94.0%, respectively, with kappa values of 0.902, 0.884 and 0.880, respectively. Tp0971, Tp0768 and Tp0462 demonstrated high sensitivities and specificities, as well as high conformity to the TPPA and LiZhu™ Tp-ELISA. Moreover, a significantly positive Spearman rank correlation coefficient (0.82,*P < 0.05) was found between the difference in the A450 nm values of the Tp0971 antibody and the RPR titre change.

Conclusion: The infection phase-dependent antigens Tp0971, Tp0768 and Tp0462 are promising for syphilis diagnosis, and Tp0971 may be utilized to monitor curative effects during syphilis treatment.

Keywords: Infection phase-dependent antigen; Serodiagnosis; Treatment efficacy; Treponema pallidum.

MeSH terms

Adolescent
Adult
Aged
Aged, 80 and over
Animals
Antigens, Bacterial / blood
Antigens, Bacterial / genetics
Antigens, Bacterial / immunology*
Child
Child, Preschool
Enzyme-Linked Immunosorbent Assay
Female
Humans
Infant
Infant, Newborn
Male
Middle Aged
Rabbits
Software
Syphilis / blood
Syphilis / drug therapy*
Syphilis / immunology*
Syphilis Serodiagnosis*
Treponema pallidum / immunology*
Treponema pallidum / isolation & purification
Young Adult

Substances

Antigens, Bacterial