Utilization of ELISA Using Thioredoxin Peroxidase-1 and Tandem Repeat Proteins for Diagnosis of Schistosoma japonicum Infection among Water Buffaloes

Abstract

BackgroundThe presence of animal reservoirs in Schistosoma japonicum infection has been a major obstacle in the control of schistosomiasis. Previous studies have proven that the inclusion of control measures on animal reservoir hosts for schistosomiasis contributed to the decrease of human cases. Animal surveillance should therefore be included to strengthen and improve the capabilities of current serological tests.Methodology/Principal FindingsThioredoxin peroxidase-1 (SjTPx-1) and four tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, Sj7TR) were initially evaluated against human sera. The previous test showed high sensitivity and specificity for antibody detection against SjTPx-1 and Sj7TR. In this study, the immunodiagnostic potential of these recombinant proteins was evaluated using enzyme-linked immunoassay on 50 water buffalo serum samples collected in Cagayan, the Philippines as compared with the soluble egg antigen (SEA). For specificity, 3 goat serum samples positive with Fasciola hepatica were used and among the antigens used, only SEA showed cross-reaction. Stool PCR targeting the S. japonicum 82 bp mitochondrial NAD 1 gene was done to confirm the true positives and served as the standard test. Twenty three samples were positive for stool PCR. SjTPx-1 and Sj1TR gave the highest sensitivity among the recombinant proteins tested for water buffalo samples with 82.61% and 78.26% respectively which were higher than that of SEA (69.57%).Conclusions/SignificanceThese results prove that SjTPx-1 works both for humans and water buffaloes making it a good candidate antigen for zoonotic diagnosis. Sj1TR showed good results for water buffaloes and therefore can also be used as a possible candidate for detecting animal schistosome infection.

Advances in the Diagnosis of Human Schistosomiasis

“…Furthermore, SjP40, an S. japonicum-specific antigen, was identified as another potential early diagnostic marker by Zhou et al (157), who measured the rise of anti-SjP40 antibody levels in rabbits during the course of infection. Moreover, the S. japonicum-specific tandem repeat antigen Sj7TR, thioredoxin peroxidase 1 (SjTPx-1), and the Sj13 protein are other molecules identified as potentially important biomarkers for use in antibody detection (272)(273)(274).…”

Immunoproteomic analysis of Schistosoma japonicum schistosomulum proteins recognized by immunoglobulin G in the sera of susceptible and non-susceptible hosts

“…In S. japonicum, TPx-1 and TPx-2 are known to exist in the tegument of the schistosomes [29,49]. Recombinant SjTPx-1 has been used as a diagnostic antigen [50] while recombinant SjTPx-2 has also been used to evaluate the efficacy of a vaccine candidate [29].…”

Characterisation and analysis of thioredoxin peroxidase as a potential antigen for the serodiagnosis of sarcoptic mange in rabbits by dot-ELISA

“…Purified TPx has been used as capture antigens for serodiagnosis of Fasciola gigantica infection, as well as Schistosoma japonicum infection in buffalo [24]. Data have also indicated that the use of specific recombinant TPx from Echinococcus granulosus as a capture antigen increased the diagnostic sensitivity of an ELISA for the detection of hydatid infection [37].…”

“…granulosus was used to screen sera from mice and patients with severe hydatid infections [23]. Furthermore, TPx is considered to be a candidate antigen for the detection of Schistosoma japonicum and Fasciola gigantica infections in water buffalo [24,25]. …”