Abstract: Objective  To analyze the immunogenicity of recombinant glutathione S-transferase protein of Fasciola hepatica（FhGST） in SD rats.  Methods  The recombinant expression plasmid pET30a-FhGST was transformed into E. coli BL21（DE3） cells and induced with IPTG for protein expression. The recombinant protein FhGST was analyzed by SDS-PAGE and identified by Western blotting. Twenty SD rats were randomly divided into two groups: immunized group and adjuvant control group. SD rats in immunized group were injected subcutaneously with 200 μg of purified FhGST protein. The adjuvant control group with 10 SD rats received only adjuvants emulsified with PBS. All the rats received three immunizations at 3-week intervals. Serum samples were collected at pre-immunization, the day after each immunization, 3 weeks and 6 weeks after the final immunization. The IgG antibody of rats’ sera was examined by indirect ELISA and spleen lymphocyte proliferation （SLP） was tested by MTT.  Results  The molecular weight of purified FhGST was about Mr 31 300. The recombinant FhGST was recognized by pool sera of goats naturally infected with F. hepatica. The recombinant protein induced specific antibody IgG against GST protein in SD rats significantly higher than that of the control, and the antibody titer reached the peak at 9 weeks after the first immunization（GMT 1 ∶ 89 144）. FhGST protein significantly enhanced the growth and proliferation of rat splenocytes.  Conclusion  The recombinant FhGST protein induces specific immune response in SD rats.

Key words: Fasciola hepatica, Glutathione S-transferase, SD rat, Immunogenicity