China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (4): 1567-1574.doi: 10.16431/j.cnki.1671-7236.2023.04.028

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Preparation and Immunogenicity Analysis of Ferritin Nanoparticles Carrying Antigenic Epitopes of Porcine Epidemic Diarrhea Virus

LIU Jiaxing1, HAN Xueying2, ZHANG Xinru1, DENG Jiaxin1, YAO Lunguang1, LIU Yangkun1   

  1. 1. Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, College of Life Science and Agricultural Engineering, Nanyang Normal University, Nanyang 473061, China;
    2. College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
  • Published:2023-04-06

Abstract: 【Objective】 The purpose of this experiment was to prepare ferritin nanoparticles carrying the epitope of Porcine epidemic diarrhea virus (PEDV) antigen and evaluate their immunogenicity,so as to provide a new candidate subunit vaccine for the prevention and control of PEDV.【Method】 The COE and S1D regions of PEDV fibrin S were designed as the tandem epitope S1CD,and the codon was optimized and synthesized.The recombinant plasmid pET28a-S1CD expressing S1CD protein alone and the recombinant plasmid pET28a-S1CD-Ferritin fusion expression S1CD protein and ferritin subunit were constructed,and then induced in E.coli and purified.SDS-PAGE and Western blotting were used to verify the expression of S1CD and S1CD-Ferritin proteins in E.coli.The morphology and structure of S1CD and S1CD-Ferritin proteins were observed by transmission electron microscope.The mice were immunized with purified S1CD-Ferritin protein,and S1CD protein and PBS were used as controls.Indirect ELISA was used to detect the level of S-specific antibody and the content of interferon-γ (IFN-γ).The level of neutralizing antibody was determined by neutralization test,and the immunogenicity of recombinant protein in mice was analyzed.【Result】 The recombinant plasmids pET28a-S1CD and pET28a-S1CD-Ferritin were successfully constructed.The result of SDS-PAGE showed that the recombinant protein S1CD and S1CD-Ferritin were efficiently expressed,with the size of about 22 and 39 ku,respectively,and both existed in the form of inclusion bodies.Western blotting results showed that the purified proteins could react specifically with the PEDV positive serum,indicating that the recombinant proteins S1CD and S1CD-Ferritin expressed by prokaryotic expression system had good reactivity.The result of transmission electron microscope showed that the purified S1CD-Ferritin protein could self-assemble into uniform nanoparticles with the diameter of 12-20 nm,indicating that S1CD-Ferritin protein had been successfully assembled into nanoparticles.Serums antibody test results showed that 7 days after the first immunization,the titer of PEDV specific antibody in S1CD-Ferritin group was significantly higher than that in S1CD group (P<0.05).28 days after the first immunization,the level of neutralizing antibody and the content of IFN-γ were significantly higher than that in S1CD group (P<0.05).【Conclusion】 The PEDV epitope fused with ferritin was highly expressed in E.coli,and could self-assemble into nanoparticles,and effectively enhance the immunogenicity of the protein antigens,which broadened the research ideas for studying new PEDV subunit vaccine.

Key words: Porcine epidemic diarrhea virus (PEDV); ferritin; nanoparticles; prokaryotic expression; immunogenicity

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