Abstract:To clone and express the cystatin gene of Agiostrongylus cantonensis(AC) and to identify the immunoprotective effect of the recombinant protein,the cystatin cDNA was subcloned into the expression vector pGEX-4T-1.Then the recombinant vector was transferred into E.coli BL21(DE3) and expressed.Mice were immunized 3 times in every week interval with the recombinant protein,and the control mice were immunized with GST protein.One week after the final immunization,all mice were challenged with the third-stage larvae of A.cantonensis.All mice were killed to count the larvae reduction rate and protection rate 3 weeks after challenge.Besides,serum levels of the cystatin-specific antibody(IgG) in mice were detected.The recombinant plasmid pGEX-4T-1-ACcystatin was constructed successfully and the fusion protein was highly expressed in E.coli in soluble form.The number of larvae of A.cantonensis were evidently reduced in mice immunized with fusion protein(P<0.01).The larvae reduction rate and protection rate were 58.1% and 20% respectively.It is evident that the cystatin gene of A.cantonensis could be high expressed in E.coli and the fusion protein can induce protective immunity in mice.
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