The immuno-protective effect induced in BALB/c mice by the UV-attenuated cercariae of Schistosoma japonicum

To investigate the immuno-protective effect induced in BALB/c mice by the UV-attenuated cercariae of Schistosoma japonicum, mice were immunized through abdominal skin, challenged 3 weeks post-immunization and were killed 6 weeks after challenge to examine the changes and to count the worm and egg reduction rates as well as to observe the developmental conditions of worms and the cell-mediated immune responses induced in liver tissues of the immunized mice. Control mice without immunization were set up for comparison. It was found that the worm and egg reduction rates of the immunized mice 37.9% and 51.16% respectively, and their developmental condition of worms was markedly delayed and less granulomatous response in liver induced by eggs was observed in comparison with the control mice. It is evident that the UV-attenuated S.japonicum cercariae can induce a middle level of immuno-protective effect in the immunized BALB/c mice.