China Animal Husbandry and Veterinary Medicine ›› 2024, Vol. 51 ›› Issue (12): 5425-5438.doi: 10.16431/j.cnki.1671-7236.2024.12.029

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Design of Multi-epitope Vaccines for Avian Pathogenic Escherichia coli O1 and O78 Serotypes Based on Subtractive Proteomics and Reverse Vaccinology

CHEN Hong1, WU Shuang1, CHE Yegui1, QIU Shulei1, ZHOU Zixiang2, WANG Yi1, WANG Yongjuan1, YUAN Cheng1   

  1. 1. Jiangsu Agri-animal Husbandry Vocational College, Taizhou 225300, China;
    2. Animal Husbandry and Veterinary Station of Liancheng Street, Huai'an 223400, China
  • Revised:2024-07-02 Published:2024-12-02

Abstract: 【Objective】 This study was aimed to design a multi-epitope vaccine (MEV) against avian pathogenic Escherichia coli (APEC) O1 and O78 serotypes,laying a foundation for the development of new vaccines for APEC.【Method】 This study combined subtraction proteomics and reverse vaccinology.Redundant and non-similar proteins in the protein sequences of APEC O1 and O78 were removed using CD-HIT and BLASTP tools.Similar proteins in APEC O1 and O78 were removed by BLASTP and compared with reference proteomes of chicken,retaining non-homologous proteins.Essential toxigenic proteins were screened using DEG,VFDB,etc.databases.Candidate proteins were selected using PSORTb and VaxiJen v 2.0.T-cell major histocompatibility complex (MHC) class Ⅰ and Ⅱ molecule-binding epitopes were predicted using NetCTL 1.2 and NetMHCⅡpan 4.0,and B-cell epitopes were predicted using IEDB.Multi-epitope vaccine were evaluated for antigenicity by VaxiJen v 2.0,and the qualified epitopes were linked together by flexible linkers to form a multi-epitope vaccine.The antigenicity,physical and chemical properties,N-glycosylation sites,secondary structure and tertiary structure of the constructed multi-epitope vaccine were predicted.The binding ability of the multi-epitope vaccine to immune receptors was evaluated by molecular docking,and the immune effect was evaluated by immune simulation.Finally,the codons were optimized for cloning and expression.【Result】 After screening,12 MHC Ⅰ,12 MHC Ⅱ and 12 B lymphocyte epitope-dominant epitopes were selected to construct the multi-epitope vaccine MEV-O1O78.The molecular mass of the multi-epitope vaccine MEV-O1O78 was 69.81 ku,a stable hydrophilic protein with good antigenicity,containing 7 potential N-glycosylation sites.In the secondary structure,alpha-helix,extended chain and random coil accounted for 7.93%,10.81% and 81.27%,respectively.The Ramachandran plot of the tertiary structure showed that the epitope-rich region contained 95.6% of the residues.The immune simulation results showed that multi-epitope MEV-O1O78 could induce good humoral immunity and enhance the expression of some cytokines.The codon optimization ensured that the designed multi-epitope MEV-O1O78 was efficiently and stably expressed in the Escherichia coli K12 expression system.【Conclusion】 In this study,the APEC O1 and O78 multi-epitope vaccine MEV-O1O78 containing 36 dominant epitopes was successfully designed,which provided theoretical basis and data support for the development of multi-epitope vaccine for avian pathogenic colibacillosis.

Key words: avian pathogenic Escherichia coli (APEC); serotype; multi-epitope vaccine

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