Application of recombinant EG95 antigen(rEG95) of Echinococcus granulosus for the detection of serum antibodies in sheep against infections of larval stage of taeniids

To evaluate the efficacy of recombinant protein on serum antibodies,EG95 gene was amplified from recombinant plasmid pGEM-EG95 by PCR,and was then subcloned into the pET-28a(+) vector.The recombinant pET-EG95 plasmid was expressed in the Escherichia coli BL21.The expressed product of rEG95 gene was identified by SDS-PAGE and Western-blotting,and purified for further use by electro-eluting method.The level of serum antibodies was determined by indirect ELISA.Results indicated that the recombinant protein rEG95 with the molecular weight of approximate 21 ku had specifically reacted with the positive sera from sheep infected with the larval stage of Echinococcus granulosus,suggesting that the protein had a promising reactinogenicity.Indirect ELISA showed that by using the rEG95 protein,thepositive rate was 66.67%,80.00%,100%,91.67% and 58.2% in 18 cases of sheep with Taenia multiceps,15 cases of Cysticercus tenuicollis,20 cases of E.granulosus,24 cases of the immunized group with rEG95 and 179 cases of an epidemic area of echinococcosis,respectively, with statistically significant diffe-rences in the positive rates among the different groups(P0.05).There was positive reactivity with ovine sera from the control healthy group. In conclusion,rEG95 protein was used as a promising antigen for the co-protective vaccine and immunodiagnostic agent of sheep with larval taeniid infections.