Serum levels of circulating anodic antigen and circulating cathodic antigen detected in mice infected withSchistosoma japonicum orS. mansoni

Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with eitherSchistosoma japonicum orS. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in theS. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in theS. 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 theS. japonicum-andS. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in theS. japonicum-infected group (27 ng/ml) as compared with theS. mansoni-infected mice (282 ng/ml). These results suggest an important difference betweenS. japonicum andS. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.