Comparison of Recombinant Proteins from Schistosoma japonicum for Schistosomiasis Diagnosis

Abstract

The most important animal reservoirs of Schistosoma japonicum in China are bovines. Diagnosis and control of bovine schistosomiasis is critical for reducing the prevalence of the disease. We screened defined diagnostic antigens that have the potential to increase the sensitivity and specificity of serological assays and to distinguish between active and prior infections. Five recombinant proteins with the potential to be diagnostic antigens were compared to the native soluble egg antigen preparation by enzyme-linked immunosorbent assay (ELISA). We evaluated the potentials of the recombinant proteins for discriminating active from prior infections, as well as the therapeutic efficacy of the established ELISA technique.

FIG. 1.

Values of OD at 490 nm determined by the 6 different antigens in ELISA with sera from bovines included in this study. The sera from 189 schistosomiasis-positive bovines diagnosed with schistosomiasis by the detection of eggs and 92 healthy bovines from Henan Province were tested by SEA and 5 recombinant protein antigens, rSjGcp-Sj23-Sj28, rSjGcp-Sj23, rSj23-LHD, rSjTPx1, and rSjEF1. The horizontal lines represent the OD cutoff values.

FIG. 2.

Correlations (A) and correlation trend lines (B) among ELISA OD values of sera analyzed with Schistosoma japonicum SEA and five Schistosoma japonicum recombinant antigens using 189 sera from schistosomiasis-positive bovines.

FIG. 3.

Antibody profiles as OD values using six antigens. Error bars represent standard deviations.

FIG. 4.

Percentages of rabbits determined as positive after treatment, as tested with six antigens.