Asian
schistosomiasis caused by Schistosoma japonicum is a serious
zoonotic disease endemic in China, the Philippines and parts of Indonesia.
Mass drug administration in endemic areas resulted to decline in disease severity and intensity. The low intensity of
infection limits the use of current parasitological methods for
schistosomiasis diagnosis. Detection of parasite circulating
antigens might provide more informative result as it may indicate the true status of
infection. In this study, S. japonicum
thioredoxin peroxidase-1 (SjTPx-1) a 22 kDa secreted
antioxidant enzyme expressed throughout the life stages of the parasite was evaluated for its potential use as a
biomarker for
schistosomiasis japonica infection. Rabbit polyclonal antibody and mouse
monoclonal antibodies (mAbs) were raised against the recombinant SjTPx-1 (rSjTPx-1). The
antibodies produced against the recombinant
antigen was confirmed to detect the native SjTPx-1 in crude adult worm lysate. Likewise, the specific binding of mAbs to parasite TPx-1 and not to mammalian peroxiredoxin-1 orthologues was also confirmed. The double antibody sandwich ELISA developed in this study was able to detect at least 1 ng/ml of rSjTPx-1. In addition, this method was able to detect the
antigen from all serum samples of experimentally infected rabbit and mice. The diagnostic potential of SjTPx-1 in human clinical samples was also evaluated, in which 4 out of 10 stool-confirmed serum samples had detectable levels of the
antigen. The results suggest that SjTPx-1 can be a potential
biomarker for Asian zoonotic
schistosomiasis.