Characterization of isoelectric point (pI) fractions of soluble egg antigen of Schistosoma japonicum.

The soluble egg antigen of Schistosoma japonicum was fractionated into 20 individual isoelectric point (pI) fractions with different pIs ranging from 1.86-11.40 by isoelectric focusing (IEF). The fractions were tested for humoral and cellular responses, as well as in vitro granuloma formations. The results indicated that the fractions in the acidic region (pI 3.78-5.54) may play an important role in granuloma elicitation in schistosomiasis japonica, and antibodies are also involved in the regulation of granuloma formation especially at the early stage (5 week postinfection).