Myoferlin is a member of the ferlin family of proteins,which are involved in plasma membrane repair,and has been identified as one of the tegument proteins of Schistosoma japonicum.The tegument proteins are potential candidates for vaccines and new drug targets.In this study,myoferlin of S.japonicum (SjMF) was cloned,expressed and characterized,the potential of SjMF recombinant protein (rSjMF) as a vaccine candidate was evaluated,and the effect ofpraziquantel on SjMF was detected by Real:time PCR.Immunofluorescence showed that this protein was mainly distributed on the surface of worms at different stages.Sequence analysis revealed that the SjMF open reading frame was conserved at all stages ofthe S.japonicum life cycle.And SjMF transeription was upregulated in 42:day:old worms,and was significantly higher in female worms.Western blotting revealed that rSjMF showed strong immunogenicity.The cytokine profile and IgG isotype analysis demonstrated that rSjMF plus ISA206 immunization induced a mixed T helper (Th)1/Th2 response.Purified rSjMF emulsified with ISA206 adjuvant significantly reduced worm burden from 21.8% to 23.21% and liver egg number from 42.58% to 28.35%.Besides,SjMF transcription was downregulated when worms were exposed to low:ddose praziquantel (PZQ) and upregulated when PZQ was degraded,accompanied by recovery of damaged tegument.When worms were exposed to high:dose PZQ,SjMF transcription was downregulated all the time and the damaged tegument did not recover.These findings indicated that SjMF is a potential vaccine against S.japonicum and provides the basis for further investigations into the biological function of SjMF.