Evaluation of six novel antigens as potential biomarkers for the early immunodiagnosis of schistosomiasis.
BACKGROUND
Early diagnosis of schistosomiasis, prior to egg laying, would enable earlier treatment and help interrupt the transmission cycle of the parasite and the progress of the disease. Previously we identified six novel antigens with potential as diagnostic markers for human Schistosoma japonicum infections. In this study, we evaluated these antigens as candidate biomarkers for the early diagnosis of schistosomiasis in mice and rabbits.


METHODS
The transcriptional profiles of the six antigens (SjSP-13, SjSP-23, SjSP-160, SjSP-164, SjSP-189 and SjSP-216) at different developmental stages were analyzed by quantitative PCR. The recombinant proteins were expressed in E. coli and purified with nickel chelate affinity chromatography. We then developed recombinant protein-based ELISA kits to analyze the kinetics of antigen-specific antibodies during the course of infection in mice and rabbits. The early diagnostic validity of the candidate SjSP-216 was further evaluated in mice and rabbits infected with S. japonicum.


RESULTS
Of the six antigens, SjSP-13, SjSP-160 and SjSP-216 were highly expressed in 21-day old young worms, while SjSP-23, SjSP-164 and SjSP-189 were highly expressed in eggs. In the mouse model, we detected a significant increase in antibodies against SjSP-13 and SjSP-216 at 3 weeks post-infection. However, in the rabbit model, only anti-SjSP-216 antibody showed a significant increase at this time point. We recorded 100 % diagnostic sensitivity and specificity of SjSP-216-based ELISA in both infected mice and rabbits, 3 weeks after infection.


CONCLUSIONS
This study strongly suggests that SjSP-216, a highly expressed gene in the young worms, could serve as a potential biomarker for the early immunodiagnosis of S. japonicum infections in vertebrate hosts.
Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, 200092, China. zyb053127@126.com.
Yuanbin
Y
Zhang
Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, 200092, China. zhj88717@live.cn.
Jing
J
Zhao
Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, 200092, China. wxy1989714@sina.com.
Xinye
X
Wang
Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, 200092, China. xuxd@tongji.edu.cn.
Xindong
X
Xu
Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, Shanghai, 200092, China. wqpan0912@aliyun.com.|Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai, 200433, China. wqpan0912@aliyun.com.
Weiqing
W
Pan
D000818:Animals; D000947:Antigens, Helminth; D015415:Biomarkers; D003001:Cloning, Molecular; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012549:Schistosoma japonicum; D012554:Schistosomiasis japonica / Q000175:diagnosis*; D012698:Serologic Tests
D000947:Antigens, Helminth; D015415:Biomarkers