Abstract:

Objective To probe a new vaccine candidate of Schistosoma japonicum, and observe the recombinant tetraspanin-4 protein (Sj-Ts4) for the immuno-protection effect on mice attacked with cercariae. Methods The BALB/c mice were immunized with the recombinant Sj-Ts4 by the dosage of 50μg/100μl, 100μg/100μl and 200μg/100μl, respectively, followed by challenging infection and the immuno-protection was evaluated. Meanwhile, the liver was removed. Some of them were digested and counted for the egg reduction rate. HE staining method was used to detect the hepatic changes and granuloma. Results The molecular vaccine was injected into BALB/c mice. The immuno-protective effect showed that the worm reduction was 22.6%, 27.1%, 30.8% in group 1, 2 and 3, respectively, and there were no remarkable significance between the groups（P<0.05）. The number of eggs in liver tissue was reduced by 31.2%, 34.29%, and 35.2%, respectively, also there were no remarkable significance between the groups（P<0.05）. Gross observation showed that the livers in control group were dark brown and hard, with massive nodules of worm eggs diffused in the livers. The recombinant Sj-Ts4 group has some extent of amelioration, the hepatic histological section demonstrated that there are generous big granulomas containing eggs in the livers of control group, with extensive infiltration of inflammatory cells, degeneration and necrosis of hepatic cells. The recombinant Sj-Ts4 vaccine group reversed the hepatic injury better than the control group. The inflammatory reaction around the eggs granulomas was light. Conclusion The molecular vaccine of rSj-Ts4 had some protection effect on mice and might be used as a latent vaccine candidate.

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