{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T11:36:24Z","timestamp":1785411384080,"version":"3.56.0"},"reference-count":27,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T00:00:00Z","timestamp":1774396800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"China Agriculture Research System","award":["CARS-41-G15"],"award-info":[{"award-number":["CARS-41-G15"]}]},{"award":["CARS-41-G15"],"award-info":[{"award-number":["CARS-41-G15"]}],"id":[{"id":"https:\/\/ror.org\/03p5eky76","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100005196","name":"Chinese Academy of Agricultural Sciences","doi-asserted-by":"crossref","award":["CAAS-CSLPDCP-202401"],"award-info":[{"award-number":["CAAS-CSLPDCP-202401"]}],"id":[{"id":"10.13039\/501100005196","id-type":"DOI","asserted-by":"crossref"}]},{"award":["CAAS-CSLPDCP-202401"],"award-info":[{"award-number":["CAAS-CSLPDCP-202401"]}],"id":[{"id":"https:\/\/ror.org\/0313jb750","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: Chicken infectious anemia virus (CIAV) is a globally significant immunosuppressive pathogen that causes substantial economic losses to the poultry industry, with particularly severe outbreaks in China in recent years. Given the limitations of existing vaccines, especially the residual virulence associated with live attenuated vaccines, there is an urgent need to develop novel, safer, and more effective vaccine strategies. Methods: In this study, the VP1 and VP2 genes of CIAV were cloned and expressed in Escherichia coli to develop a cost-effective subunit vaccine. Since VP1 primarily formed inclusion bodies, a \u201cVP2-assisted co-refolding\u201d strategy was employed. This involved denaturing VP1 and refolding it via gradient dialysis in the presence of soluble VP2, thereby leveraging VP2\u2019s natural chaperone-like function to restore conformational epitopes. The refolded VP1\/VP2 protein complexes, emulsified at different ratios, were used to immunize 3-day-old specific pathogen-free (SPF) chickens, followed by challenge with a virulent CIAV strain. Results: The vaccine formulation with a VP1:VP2 ratio of 1:1 provided the best protection, achieving 71.4% (5\/7) protective efficacy, as evidenced by significantly reduced thymic atrophy and a higher thymus index. Conclusions: These findings validate the feasibility of using an economical prokaryotic expression system combined with a rational protein refolding strategy to produce a protective subunit vaccine candidate against CIAV, offering a promising alternative for disease control.<\/jats:p>","DOI":"10.3390\/vaccines14040292","type":"journal-article","created":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T10:07:13Z","timestamp":1774433233000},"page":"292","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Recombinant Subunit Vaccine Against Chicken Infectious Anemia Virus Elicits Protective Immunity via VP2-Assisted VP1 Refolding"],"prefix":"10.3390","volume":"14","author":[{"given":"Shihao","family":"Li","sequence":"first","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingxue","family":"Hu","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanping","family":"Zhang","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yulu","family":"Duan","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ru","family":"Guo","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huijing","family":"Sun","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenzhuo","family":"Ma","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaole","family":"Qi","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongyu","family":"Cui","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suyan","family":"Wang","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuntong","family":"Chen","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongzhen","family":"Liu","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0448-8467","authenticated-orcid":false,"given":"Yulong","family":"Gao","sequence":"additional","affiliation":[{"name":"Avian Immunosuppressive Diseases Division, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1080\/03079459108418756","article-title":"Chicken anaemia agent: A review","volume":"20","author":"McNulty","year":"1991","journal-title":"Avian Pathol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1080\/03079457.2021.1919289","article-title":"Origin, spreading and genetic variability of chicken anaemia virus","volume":"50","author":"Techera","year":"2021","journal-title":"Avian Pathol."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Fang, L., Jia, H., Hu, Y., Wang, Y., Cui, Z., Qi, L., and Zhao, P. (2023). Molecular characterization and pathogenicity study of a highly pathogenic strain of chicken anemia virus that emerged in China. Front. Cell. Infect. Microbiol., 13.","DOI":"10.3389\/fcimb.2023.1171622"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3131","DOI":"10.1128\/jvi.65.6.3131-3139.1991","article-title":"Characterization of cloned chicken anemia virus DNA that contains all elements for the infectious replication cycle","volume":"65","author":"Noteborn","year":"1991","journal-title":"J. Virol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.micpath.2016.05.003","article-title":"Impact of virus load on immunocytological and histopathological parameters during clinical chicken anemia virus (CAV) infection in poultry","volume":"96","author":"Wani","year":"2016","journal-title":"Microb. Pathog."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"7383","DOI":"10.1128\/jvi.66.12.7383-7388.1992","article-title":"Chicken anemia virus causes apoptosis of thymocytes after in vivo infection and of cell lines after in vitro infection","volume":"66","author":"Jeurissen","year":"1992","journal-title":"J. Virol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1046\/j.1365-2567.2003.01643.x","article-title":"Infection with chicken anaemia virus impairs the generation of pathogen-specific cytotoxic T lymphocytes","volume":"109","author":"Schat","year":"2003","journal-title":"Immunology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1080\/03079457.2011.586330","article-title":"Chicken infectious anaemia vaccinal strain persists in the spleen and thymus of young chicks and induces thymic lymphoid cell disorders","volume":"40","author":"Vaziry","year":"2011","journal-title":"Avian Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1111\/j.1865-1682.2011.01215.x","article-title":"Prevalence of chicken infectious anaemia virus (CIAV) in commercial poultry flocks of northern India: A serological survey","volume":"58","author":"Bhatt","year":"2011","journal-title":"Transbound. Emerg. Dis."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Zhang, Y., Cui, N., Han, N., Wu, J., Cui, Z., and Su, S. (2017). Depression of vaccinal immunity to Marek\u2019s disease by infection with chicken infectious anemia virus. Front. Microbiol., 8.","DOI":"10.3389\/fmicb.2017.01863"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"707","DOI":"10.2307\/1591148","article-title":"The isolation and characterization of chicken anemia agent (CAA) from broilers in the United States","volume":"33","author":"Rosenberger","year":"1989","journal-title":"Avian Dis."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1916","DOI":"10.1016\/j.vaccine.2015.02.066","article-title":"Assessing the efficacy of an inactivated chicken anemia virus vaccine","volume":"33","author":"Zhang","year":"2015","journal-title":"Vaccine"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1080\/03079457.2019.1637821","article-title":"Chicken infectious anaemia virus infections in chickens in northern Vietnam: Epidemiological features and genetic characterization of the causative agent","volume":"49","author":"Huynh","year":"2020","journal-title":"Avian Pathol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/j.vaccine.2014.11.020","article-title":"Development of a DNA vaccine for chicken infectious anemia and its immunogenicity studies using high mobility group box 1 protein as a novel immunoadjuvant","volume":"33","author":"Sawant","year":"2015","journal-title":"Vaccine"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Tseng, T.-Y., Liu, Y.-C., Hsu, Y.-C., Chang, P.-C., Hsieh, M.-K., Shien, J.-H., and Ou, S.-C. (2019). Preparation of chicken anemia virus (CAV) virus-like particles and chicken interleukin-12 for vaccine development using a baculovirus expression system. Pathogens, 8.","DOI":"10.3390\/pathogens8040262"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"763","DOI":"10.1016\/0264-410X(94)00034-K","article-title":"Immunogenic and protective properties of chicken anaemia virus proteins expressed by baculovirus","volume":"13","author":"Koch","year":"1995","journal-title":"Vaccine"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Lai, G.-H., Lin, M.-K., Lien, Y.-Y., Cheng, J.-H., Sun, F.-C., Lee, M.-S., Chen, H.-J., and Lee, M.-S. (2018). Characterization of the DNA binding activity of structural protein VP1 from chicken anaemia virus. BMC Vet. Res., 14.","DOI":"10.1186\/s12917-018-1465-5"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1186\/1475-2859-10-56","article-title":"High yield expression in a recombinant E. coli of a codon optimized chicken anemia virus capsid protein VP1 useful for vaccine development","volume":"10","author":"Lee","year":"2011","journal-title":"Microb. Cell Fact."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Lai, G.-H., Lin, M.-K., Lien, Y.-Y., Fu, J.-H., Chen, H.-J., Huang, C.-H., Tzen, J.T., and Lee, M.-S. (2013). Expression and characterization of highly antigenic domains of chicken anemia virus viral VP2 and VP3 subunit proteins in a recombinant E. coli for sero-diagnostic applications. BMC Vet. Res., 9.","DOI":"10.1186\/1746-6148-9-161"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"39566","DOI":"10.1074\/jbc.M201752200","article-title":"Chicken anemia virus VP2 is a novel dual specificity protein phosphatase","volume":"277","author":"Peters","year":"2002","journal-title":"J. Biol. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/0378-1135(94)90097-3","article-title":"Cloning and sequencing of the chicken anaemia virus (CAV) ORF-3 gene, and the development of an ELISA for the detection of serum antibody to CAV","volume":"39","author":"Pallister","year":"1994","journal-title":"Vet. Microbiol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.vetimm.2015.08.002","article-title":"Development of a subunit vaccine containing recombinant chicken anemia virus VP1 and pigeon IFN-\u03b3","volume":"167","author":"Shen","year":"2015","journal-title":"Vet. Immunol. Immunopathol."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Liu, L., Yin, M., Li, Y., Su, H., Fang, L., Sun, X., Chang, S., Zhao, P., and Wang, Y. (2022). DNA prime and recombinant protein boost vaccination confers chickens with enhanced protection against chicken infectious anemia virus. Viruses, 14.","DOI":"10.3390\/v14102115"},{"key":"ref_24","unstructured":"Patterson, A.R., and Opriessnig, T. (2020). Epidemiology and vaccine efficacy of porcine circovirus type 2d (PCV2d). Vaccines, 8."},{"key":"ref_25","first-page":"1","article-title":"Efficient expression and purification of porcine circovirus type 2 virus-like particles in Escherichia coli","volume":"122","author":"Zhang","year":"2016","journal-title":"Protein Expr. Purif."},{"key":"ref_26","first-page":"2456","article-title":"Optimized production of full-length PCV2d virus-like particles in Escherichia coli: A cost-effective and high-yield approach for potential vaccine antigen development","volume":"42","author":"Wang","year":"2024","journal-title":"Vaccine"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1177","DOI":"10.1007\/s00253-012-4015-2","article-title":"Characterization of porcine circovirus type 2 (PCV2) capsid particle assembly and its application to virus-like particle vaccine development","volume":"95","author":"Wu","year":"2012","journal-title":"Appl. Microbiol. Biotechnol."}],"container-title":["Vaccines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-393X\/14\/4\/292\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T16:03:50Z","timestamp":1775059430000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-393X\/14\/4\/292"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,25]]},"references-count":27,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["vaccines14040292"],"URL":"https:\/\/doi.org\/10.3390\/vaccines14040292","relation":{},"ISSN":["2076-393X"],"issn-type":[{"value":"2076-393X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,25]]}}}