Antigenicity Assay of the Expression Product of Fusion Gene of Truncated HBV Core Gene and “a” Determinant Gene

Objective To evaluate the antigenicity of expression products of the fusion gene of truncated HBV core gene and gene of “a” determinant region.Methods The major immunodominant region of truncated HBV core gene was replaced with “a” determinant region of HBV gene and then the chimeric gene was cloned into the MCS region of prokaryotic expression vector-pREST-B. After inducing the fusion gene expressed in E.Coli by IPTG, we analyzed the antigenicity of fusion protein by ELISA and Western blot. Then the chimeric gene was subcloned into eukaryotic expression vector pcDNA3. After transient transfection of the BHK cells, we detected the antigenicity of fusion protein by IFA.Results The chimeric gene of truncated HBV core gene and “a” determinant gene was expressed successfully in E.coli BL21(DE3)plysS. ELISA and Western blot assay showed that the expressed 28 ku protein has the antigenicity of HBsAg and the major antigenicity of HBcAg was deleted successfully. The chimeric gene could also express in BHK cell line and the fusion protein had the good antigenicity of HBsAg and the antigenicity of HBcAg was weak.Conclusion The expression product of chimeric gene has good antigennicity of HBsAg and maintains the antigennicity of HbcAg to some degrees.