Serum levels of circulating anodic antigen and circulating cathodic antigen detected in mice infected with Schistosoma japonicum or S. mansoni.

Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with either Schistosoma japonicum or S. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in the S. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in the S. mansoni-infected group during the full study period. At the moment of perfusion, 10 weeks p.i., a median of 9 and 29 worms, respectively, were recovered from the S. japonicum- and S. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in the S. japonicum-infected group (27 ng/ml) as compared with the S. mansoni-infected mice (282 ng/ml). These results suggest an important difference between S. japonicum and S. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.