China Animal Husbandry and Veterinary Medicine ›› 2021, Vol. 48 ›› Issue (12): 4652-4660.doi: 10.16431/j.cnki.1671-7236.2021.12.033

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Eukaryotic Expression and Immunogenicity Detection of Fusion Protein of Chicken Infectious Bursal Disease Virus VP2 and Truncated Diphtheria Toxin DT390

MENG Weijin1, FAN Kuohai2, CHANG Xiongxiong1, YIN Wei1, LI Hongquan1, WANG Zhirui1   

  1. 1. Clinical Veterinary Laboratory, College of Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, China;
    2. Laboratory Animal Management Center of Shanxi Agricultural University, Taigu 030801, China
  • Received:2021-04-22 Online:2021-12-20 Published:2021-12-02

Abstract: In order to explore whether truncated diphtheria toxin DT390 had immune enhancing effect on VP2 protein of Infectious bursal disease virus (IBDV), in this study, DT390 and VP2 were fused and expressed by Pichia pastoris expression system with diphtheria toxin resistance.The expressed fusion protein DT390-VP2 was identified by SDS-PAGE and Western blotting.Twenty four 21 days old SPF chicks were randomly divided into four groups:VP2 group, DT390-VP2 group, PBS (control group) and B87 group (positive control group).The chicks in each group were immunized on the the 0 and 14th days, respectively.On the 28th day after the first immunization, each chick was inoculated with IBDV BC6/85 strain of 100 BID50.The serum VP2 specific antibody levels of chicks in each group at different time before and after immunization were detected by ELISA.HE staining and pathological damage score were used to evaluate the damage degree of Fabricius, and the immunogenicity and protective function of fusion protein DT390-VP2 in chicks.SDS-PAGE and Western blotting analysis showed that the expressed and purified target protein was glycosylated fusion protein DT390-VP2 (91.26 ku).The results of in vivo test showed that 21 days after the first immunization, the titer of VP2 specific antibody in DT390-VP2 group was significantly and extremely significantly higher than that in B87 group (P<0.05) and VP2 group (P<0.01), respectively.28 days after the first immunization, the titer of VP2 specific antibody in DT390-VP2 group was extremely significantly higher than that in VP2 group (P<0.01).Compared with VP2 protein, the fusion protein DT390-VP2 reduced the atrophy of bursal lymph follicles in chicks.In conclusion, truncated diphtheria toxin DT390 enhanced the humoral immunogenicity of VP2 by fusion expression, the fusion protein DT390-VP2 reduced the damage of tissue caused by IBDV BC6/85 strain to a certain extent.

Key words: Infectious bursal disease virus (IBDV); VP2 protein; DT390; immunogenicity

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