Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus

IntroductionInfectious bursal disease (IBD) is a severe immunosuppressive disease caused by the infection of infectious bursal disease virus (IBDV) in chicken. Recently, an emerging mutant named novel variant IBDV (nVarIBDV) has rapidly spread in China and become a prevalent strain. However, little...

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Main Authors: Haifeng Xiong, Jiayan Wu, Quan Xie, Tuofan Li, Zhimin Wan, Aijian Qin, Jianqiang Ye, Hongxia Shao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2025.1600371/full
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author Haifeng Xiong
Haifeng Xiong
Haifeng Xiong
Jiayan Wu
Jiayan Wu
Jiayan Wu
Quan Xie
Quan Xie
Quan Xie
Quan Xie
Tuofan Li
Tuofan Li
Tuofan Li
Tuofan Li
Zhimin Wan
Zhimin Wan
Zhimin Wan
Zhimin Wan
Aijian Qin
Aijian Qin
Aijian Qin
Aijian Qin
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Hongxia Shao
Hongxia Shao
Hongxia Shao
Hongxia Shao
author_facet Haifeng Xiong
Haifeng Xiong
Haifeng Xiong
Jiayan Wu
Jiayan Wu
Jiayan Wu
Quan Xie
Quan Xie
Quan Xie
Quan Xie
Tuofan Li
Tuofan Li
Tuofan Li
Tuofan Li
Zhimin Wan
Zhimin Wan
Zhimin Wan
Zhimin Wan
Aijian Qin
Aijian Qin
Aijian Qin
Aijian Qin
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Hongxia Shao
Hongxia Shao
Hongxia Shao
Hongxia Shao
author_sort Haifeng Xiong
collection DOAJ
description IntroductionInfectious bursal disease (IBD) is a severe immunosuppressive disease caused by the infection of infectious bursal disease virus (IBDV) in chicken. Recently, an emerging mutant named novel variant IBDV (nVarIBDV) has rapidly spread in China and become a prevalent strain. However, little is known about the unique antigenic sites of nVarIBDV escaped from current IBDV vaccines.MethodsHere, the expressed hypervariable region (HVR) of VP2 (VP2-HVR) of nVarIBDV was used as an immunogen and a novel monoclonal antibody (mAb) against VP2 (mAb 5B5) was generated.ResultsImmunofluorescence assay (IFA) and ELISA demonstrated that mAb 5B5 specifically reacted with nVarIBDV and its VP2 protein, but not with classical IBDV (cIBDV), very virulent IBDV (vvIBDV), or attenuated IBDV (attIBDV) strains. Epitope mapping and site mutagenesis assay revealed that mAb 5B5 recognized the conformational epitope in peak A (212–224 aa) and heptapeptide (326–332 aa) regions, and identified residue 221K in VP2 as the key antigenic site, which is conserved exclusively in nVarIBDV strains. Notably, K221Q mutation in VP2 of nVarIBDV significantly altered the reaction profile for sera against vvIBDV or cIBDV. Neutralization assays revealed that mAb 5B5 could inhibit replication of an engineered attIBDV carrying 221K in Leghorn male hepatoma (LMH) cells. Structural analysis further found that 221K is surface-exposed and alters local electrostatic potential, possibly facilitating immune evasion.DiscussionAll these demonstrated that 221K is a unique antigenic site in VP2 of nVarIBDV associated with immune escape, providing novel insights into the antigenicity of nVarIBDV and novel targets for efficient diagnostics, vaccine design, and molecular surveillance of IBDV.
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spelling doaj-art-4af110c6e4e04ad196fabf5be20e54f92025-08-20T03:17:26ZengFrontiers Media S.A.Frontiers in Immunology1664-32242025-07-011610.3389/fimmu.2025.16003711600371Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virusHaifeng Xiong0Haifeng Xiong1Haifeng Xiong2Jiayan Wu3Jiayan Wu4Jiayan Wu5Quan Xie6Quan Xie7Quan Xie8Quan Xie9Tuofan Li10Tuofan Li11Tuofan Li12Tuofan Li13Zhimin Wan14Zhimin Wan15Zhimin Wan16Zhimin Wan17Aijian Qin18Aijian Qin19Aijian Qin20Aijian Qin21Jianqiang Ye22Jianqiang Ye23Jianqiang Ye24Jianqiang Ye25Hongxia Shao26Hongxia Shao27Hongxia Shao28Hongxia Shao29Key Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaKey Laboratory of Jiangsu Preventive Veterinary Medicine, Key Laboratory for Avian Preventive Medicine, Ministry of Education, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, ChinaInstitutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, Jiangsu, ChinaIntroductionInfectious bursal disease (IBD) is a severe immunosuppressive disease caused by the infection of infectious bursal disease virus (IBDV) in chicken. Recently, an emerging mutant named novel variant IBDV (nVarIBDV) has rapidly spread in China and become a prevalent strain. However, little is known about the unique antigenic sites of nVarIBDV escaped from current IBDV vaccines.MethodsHere, the expressed hypervariable region (HVR) of VP2 (VP2-HVR) of nVarIBDV was used as an immunogen and a novel monoclonal antibody (mAb) against VP2 (mAb 5B5) was generated.ResultsImmunofluorescence assay (IFA) and ELISA demonstrated that mAb 5B5 specifically reacted with nVarIBDV and its VP2 protein, but not with classical IBDV (cIBDV), very virulent IBDV (vvIBDV), or attenuated IBDV (attIBDV) strains. Epitope mapping and site mutagenesis assay revealed that mAb 5B5 recognized the conformational epitope in peak A (212–224 aa) and heptapeptide (326–332 aa) regions, and identified residue 221K in VP2 as the key antigenic site, which is conserved exclusively in nVarIBDV strains. Notably, K221Q mutation in VP2 of nVarIBDV significantly altered the reaction profile for sera against vvIBDV or cIBDV. Neutralization assays revealed that mAb 5B5 could inhibit replication of an engineered attIBDV carrying 221K in Leghorn male hepatoma (LMH) cells. Structural analysis further found that 221K is surface-exposed and alters local electrostatic potential, possibly facilitating immune evasion.DiscussionAll these demonstrated that 221K is a unique antigenic site in VP2 of nVarIBDV associated with immune escape, providing novel insights into the antigenicity of nVarIBDV and novel targets for efficient diagnostics, vaccine design, and molecular surveillance of IBDV.https://www.frontiersin.org/articles/10.3389/fimmu.2025.1600371/fullnVarIBDVVP2mAb221Kantigenicitydifferentiation
spellingShingle Haifeng Xiong
Haifeng Xiong
Haifeng Xiong
Jiayan Wu
Jiayan Wu
Jiayan Wu
Quan Xie
Quan Xie
Quan Xie
Quan Xie
Tuofan Li
Tuofan Li
Tuofan Li
Tuofan Li
Zhimin Wan
Zhimin Wan
Zhimin Wan
Zhimin Wan
Aijian Qin
Aijian Qin
Aijian Qin
Aijian Qin
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Jianqiang Ye
Hongxia Shao
Hongxia Shao
Hongxia Shao
Hongxia Shao
Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
Frontiers in Immunology
nVarIBDV
VP2
mAb
221K
antigenicity
differentiation
title Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
title_full Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
title_fullStr Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
title_full_unstemmed Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
title_short Q221K mutation in VP2 drives antigenic shift of infectious bursal disease virus
title_sort q221k mutation in vp2 drives antigenic shift of infectious bursal disease virus
topic nVarIBDV
VP2
mAb
221K
antigenicity
differentiation
url https://www.frontiersin.org/articles/10.3389/fimmu.2025.1600371/full
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