关键词: 猪瘟病毒囊膜蛋白E2, 纳米颗粒抗原, 铁蛋白

Abstract: At present, the traditional inactivated and attenuated classical swine fever vaccines have some shortcomings, such as short immune protection period and strong virulence, and protein-derived subunit vaccines can solve these problems well.  24 subunits of ferritin can be self-assembled into stable multimeric nanoparticles, and become an ideal  antigen presentation carrier and vaccine development platform. Based on this, ferritin was combined with classical swine fever virus envelope protein E2 (protective antigen with high conservation) to construct a fusion gene E2-Fe, which was cloned into pET28a prokaryotic expression vector and then transformed into competent cells of Escherichia coli BL21 (DE3) to explore the induction conditions and express it efficiently. Then the expressed fusion protein was purified by nickel column, analyzed by mass spectrometry, verified by Western-blotting, and detected by electron microscope. The results showed that the fusion gene E2-Fe had been successfully cloned into pET-28a vector, and the best expression condition of fusion protein E2-Fe was induced by 0.50% lactose for 6 h. Mass spectrometry analysis and Western-blotting showed that the size of the fusion protein was about 51 kD, which was consistent with the theoretical value. The diameter of nanoparticles observed by electron microscope was about 20 nm. The results showed that the envelope protein E2 of classical swine fever virus fused with ferritin was highly expressed in E. coli, and a considerable amount of self-assembled nanoparticle antigens could be obtained after purification by nickel column, which broadened the research ideas for studying new classical swine fever vaccines.

Key words: swine fever virus envelope protein E2, nanoparticle antigen, ferritin