Proteomic patterns as biomarkers for the early detection of schistosomiasis japonica in a rabbit model

The objective of this study was to identify proteomic patterns in sera for the early detection of Schistosoma japonicum infections in a rabbit model. Proteomic patterns were to be established by profiling serum proteins using magnetic bead (MB) separation and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Forty rabbits were randomly allocated to two groups. One group was infected with 1500 S. japonicum cercariae, the other served as non-infected control. An additional group of Toxoplasma gondii-infected rabbits served as specificity control group. Sera were obtained from each rabbit once a week post-infection and were subject to weak cation exchange beads (MB-WCX) treatment, followed by MALDI-TOF MS analysis. The proteomic pattern of infected and control rabbits was established 7 weeks post-infection with the ClinProTool MS data analysis program. Seven peaks with a clear difference in amplitude between the infected and control groups were detected, 4 peaks with mass charge ratio (m/z) of 1787, 2834, 3484 and 3531 were up-regulated and 3 peaks with a m/z of 1715, 3151 and 4018 were down-regulated in infected rabbits. The established diagnostic proteomic pattern was highly sensitive and specific. In weeks 1–4 post-infection, characteristic proteomic patterns could be detected in 30%, 55%, 75% and 80% of the infected rabbits, whereas ELISA testing resulted in positive results from week 3 onwards. All T. gondii control sera were classified S. japonicum negative. MALDI-TOF MS coupled with MB separation enables early, rapid and accurate diagnosis of schistosomiasis in a rabbit model.