Abstract: Observations on the immunoreactivities toward egg antigens of different experimental animals infected with Schistosoma japonicum were made,which included mouse,rat,hamster,rabbit and rhesus monkey.The cercariae applied for infection were shed by snails collected from 5 different isolates,i.e.,Anhui,Hubei,Sichuan,Yunnan and Guangxi in the mainland of China.Sera from the same sort of animals were separately pooled according to the different sources of infection mentioned above.Antibody reactivities were evaluated by COPT,LAT and ELISA.In COPT each serum sample was tested with ova from homologous and heterologous isolates,whereas soluble egg antigen merely prepared from Anhui isolate was used in LAT and ELISA.The level of antibodies detected by homologous or heterologous worm isolate antigens was compared.The results suggested that the positive antibody defection rate might not be influenced by antigens prepared from S.japonicum eggs of different isolates in the mainland of China.