[Prokaryotic expression and characterization of N-terminal truncated glycoprotein gp85 of Epstein-Barr virus].

Aim: To construct a prokaryotic recombinant vector of Epstein-Barr virus (EBV) membrane protein gp85, to express the protein in E.coli and characterize the antigenicity of this non-glycosylated protein.

Methods: The BXLF2 gene coding 5'-terminal truncated of EBV gp85 was amplified from the EBV strain B95-8 cell line with specific primers. After identification by the restriction digestion with Hind III and Xho I, the PCR product was inserted into the prokaryotic expression plasmid pGEX-5T and confirmed by sequencing. The constructed prokaryotic expression vector pGEX5T-85N was transformed into the competent E.coli BL21. The expressed recombinant protein gp85N was purified by affinity chromatography, characterized by Western blot, and used immunize BALB/c mice. The titer of antiserum from the immunized mice was detected by ELISA.

Results: Sequencing analysis revealed that the obtained truncated BXLF2 gene was identical to that published in GenBank and successfully cloned into pGEX-5T. SDS-PAGE showed that the expressed recombinant protein was partially soluble with a relative molecular mass of 45,000. ELISA results indicated that the expressed gp85N was recognized by that the anti-gp85 mAb and contiserum with high titer was obtained from the immunized mice.

Conclusion: The obtained recombinant gp85N with an excellent antigenicity should provide preliminary data for characterization of the antibody produced by the immunized mice.