{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T19:32:47Z","timestamp":1769196767999,"version":"3.49.0"},"reference-count":53,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,8,18]],"date-time":"2021-08-18T00:00:00Z","timestamp":1629244800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Foundation of Korea (NRF)","award":["2018R1A6A1A03025124"],"award-info":[{"award-number":["2018R1A6A1A03025124"]}]},{"name":"Ministry of Health &amp; Welfare, Republic of Korea","award":["HV20C0085, HV20C0142"],"award-info":[{"award-number":["HV20C0085, HV20C0142"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>The ongoing severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic had brought disastrous consequences throughout the entire world. While several manufactured vaccines have been approved for emergency use, continuous efforts to generate novel vaccines are needed. In this study, we developed SARS-CoV-2 virus-like particles (VLPs) containing the full length of spike (S) glycoprotein (S full), S1, or S2 together with the influenza matrix protein 1 (M1) as a core protein. Successfully constructed VLPs expressing the S full, S1, and S2 via Sf9 cell transfections were confirmed and characterized by Western blot and transmission electron microscopy (TEM). VLP immunization in mice induced higher levels of spike protein-specific IgG and its subclasses compared to na\u00efve control, with IgG2a being the most predominant subclass. S full and S1 immune sera elicited virus-neutralizing activities, but these were not strong enough to fully inhibit receptor\u2013ligand binding of the SARS-CoV-2. Neutralizing activities were not observed from the S2 VLP immune sera. Overall, our findings revealed that S full or S1 containing VLPs can be developed into effective vaccines.<\/jats:p>","DOI":"10.3390\/vaccines9080920","type":"journal-article","created":{"date-parts":[[2021,8,18]],"date-time":"2021-08-18T22:51:00Z","timestamp":1629327060000},"page":"920","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Influenza Virus-like Particle (VLP) Vaccines Expressing the SARS-CoV-2 S Glycoprotein, S1, or S2 Domains"],"prefix":"10.3390","volume":"9","author":[{"given":"Ki-Back","family":"Chu","sequence":"first","affiliation":[{"name":"Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hae-Ji","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keon-Woong","family":"Yoon","sequence":"additional","affiliation":[{"name":"Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hae-Ahm","family":"Lee","sequence":"additional","affiliation":[{"name":"Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1121-2052","authenticated-orcid":false,"given":"Eun-Kyung","family":"Moon","sequence":"additional","affiliation":[{"name":"Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4406-6226","authenticated-orcid":false,"given":"Beom-Ku","family":"Han","sequence":"additional","affiliation":[{"name":"Optipharm Inc., Cheongju 28158, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0419-9339","authenticated-orcid":false,"given":"Fu-Shi","family":"Quan","sequence":"additional","affiliation":[{"name":"Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea"},{"name":"Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1186\/s12985-019-1182-0","article-title":"Coronavirus envelope protein: Current knowledge","volume":"16","author":"Schoeman","year":"2019","journal-title":"Virol. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1177\/135965350701200S01.1","article-title":"Human coronaviruses: What do they cause?","volume":"12","year":"2007","journal-title":"Antivir. Ther."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1056\/NEJMoa2001017","article-title":"A Novel Coronavirus from Patients with Pneumonia in China, 2019","volume":"382","author":"Zhu","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3055","DOI":"10.1080\/21645515.2020.1796425","article-title":"Role of antibody-dependent enhancement (ADE) in the virulence of SARS-CoV-2 and its mitigation strategies for the development of vaccines and immunotherapies to counter COVID-19","volume":"16","author":"Karthik","year":"2020","journal-title":"Hum. Vaccin. Immunother."},{"key":"ref_5","unstructured":"WHO (2021, April 21). WHO Coronavirus (COVID-19) Dashboard. Available online: https:\/\/covid19.who.int\/."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1038\/s41586-020-2012-7","article-title":"A pneumonia outbreak associated with a new coronavirus of probable bat origin","volume":"579","author":"Zhou","year":"2020","journal-title":"Nature"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1038\/d41573-020-00151-8","article-title":"Evolution of the COVID-19 vaccine development landscape","volume":"19","author":"Le","year":"2020","journal-title":"Nat. Rev. Drug Discov."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2603","DOI":"10.1056\/NEJMoa2034577","article-title":"Safety and Efficacy of the BNT162b2 mRNA COVID-19 Vaccine","volume":"383","author":"Polack","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1885","DOI":"10.1056\/NEJMoa2102214","article-title":"Efficacy of the ChAdOx1 nCoV-19 COVID-19 Vaccine against the B.1.351 Variant","volume":"384","author":"Madhi","year":"2021","journal-title":"N. Engl. J. Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"26","DOI":"10.4161\/hv.22218","article-title":"Plant-derived virus-like particles as vaccines","volume":"9","author":"Chen","year":"2013","journal-title":"Hum. Vaccin. Immunother."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1007\/s11908-021-00752-3","article-title":"Status Report on COVID-19 Vaccines Development","volume":"23","author":"Kumar","year":"2021","journal-title":"Curr. Infect. Dis. Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"862","DOI":"10.3389\/fbioe.2020.00862","article-title":"Construction of SARS-CoV-2 Virus-Like Particles by Mammalian Expression System","volume":"8","author":"Xu","year":"2020","journal-title":"Front. Bioeng. Biotechnol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1259","DOI":"10.1021\/acsnano.0c08430","article-title":"Biomimetic Virus-Like Particles as Severe Acute Respiratory Syndrome Coronavirus 2 Diagnostic Tools","volume":"15","author":"Chan","year":"2021","journal-title":"ACS Nano"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"198305","DOI":"10.1016\/j.virusres.2021.198305","article-title":"A stable platform for the production of virus-like particles pseudotyped with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein","volume":"295","author":"Roy","year":"2021","journal-title":"Virus Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"542","DOI":"10.1038\/s41467-020-20654-7","article-title":"A COVID-19 vaccine candidate using SpyCatcher multimerization of the SARS-CoV-2 spike protein receptor-binding domain induces potent neutralising antibody responses","volume":"12","author":"Tan","year":"2021","journal-title":"Nat. Commun."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Yang, Y., Shi, W., Abiona, O.M., Nazzari, A., Olia, A.S., Ou, L., Phung, E., Stephens, T., Tsybovsky, Y., and Verardi, R. (2021). Newcastle Disease Virus-Like Particles Displaying Prefusion-Stabilized SARS-CoV-2 Spikes Elicit Potent Neutralizing Responses. Vaccines, 9.","DOI":"10.3390\/vaccines9020073"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4064","DOI":"10.1016\/j.vaccine.2017.06.003","article-title":"The complexity and cost of vaccine manufacturing\u2014An overview","volume":"35","author":"Plotkin","year":"2017","journal-title":"Vaccine"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Chu, K.B., and Quan, F.S. (2021). Virus-Like Particle Vaccines Against Respiratory Viruses and Protozoan Parasites. Curr. Top. Microbiol Immunol., 1\u201330.","DOI":"10.1007\/82_2021_232"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Kang, H.J., Chu, K.B., Lee, D.H., Lee, S.H., Park, B.R., Kim, M.C., Kang, S.M., and Quan, F.S. (2019). Influenza M2 virus-like particle vaccination enhances protection in combination with avian influenza HA VLPs. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0216871"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"11813","DOI":"10.1128\/JVI.01076-08","article-title":"Incorporation of membrane-anchored flagellin into influenza virus-like particles enhances the breadth of immune responses","volume":"82","author":"Wang","year":"2008","journal-title":"J. Virol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5692","DOI":"10.1016\/j.vaccine.2018.08.016","article-title":"Virus-like particle vaccines expressing Toxoplasma gondii rhoptry protein 18 and microneme protein 8 provide enhanced protection","volume":"36","author":"Lee","year":"2018","journal-title":"Vaccine"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1080\/08820139.2018.1544640","article-title":"Immune Correlates of Protection Induced by Virus-Like Particles Containing 2009 H1N1 Pandemic Influenza HA, NA or M1 Proteins","volume":"48","author":"Moon","year":"2019","journal-title":"Immunol. Invest."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"pdb-prot5395","DOI":"10.1101\/pdb.prot5395","article-title":"Immunofluorescence analysis of baculovirus-displayed viral proteins on infected insect cells","volume":"2010","author":"Ernst","year":"2010","journal-title":"Cold Spring Harb. Protoc."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Chu, K.B., Lee, H.A., Kang, H.J., Moon, E.K., and Quan, F.S. (2020). Preliminary Trichinella spiralis Infection Ameliorates Subsequent RSV Infection-Induced Inflammatory Response. Cells, 9.","DOI":"10.3390\/cells9051314"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1038\/s41587-020-0631-z","article-title":"A SARS-CoV-2 surrogate virus neutralization test based on antibody-mediated blockage of ACE2-spike protein-protein interaction","volume":"38","author":"Tan","year":"2020","journal-title":"Nat. Biotechnol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/0378-1119(91)90171-7","article-title":"Enhanced secretion from insect cells of a foreign protein fused to the honeybee melittin signal peptide","volume":"98","author":"Tessier","year":"1991","journal-title":"Gene"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"95","DOI":"10.15585\/mmwr.mm7003e2","article-title":"Emergence of SARS-CoV-2 B.1.1.7 Lineage\u2014United States, December 29, 2020\u2013January 12, 2021","volume":"70","author":"Galloway","year":"2021","journal-title":"MMWR Morb. Mortal Wkly. Rep."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e27","DOI":"10.1016\/j.jinf.2020.12.024","article-title":"Emergence of a new SARS-CoV-2 variant in the UK","volume":"82","author":"Tang","year":"2021","journal-title":"J. Infect."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3432","DOI":"10.1128\/JVI.03004-13","article-title":"Assessment of influenza virus hemagglutinin stalk-based immunity in ferrets","volume":"88","author":"Krammer","year":"2014","journal-title":"J. Virol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"e00018-10","DOI":"10.1128\/mBio.00018-10","article-title":"Influenza virus vaccine based on the conserved hemagglutinin stalk domain","volume":"1","author":"Steel","year":"2010","journal-title":"MBio"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"10435","DOI":"10.1128\/JVI.01715-13","article-title":"Hemagglutinin stalk-based universal vaccine constructs protect against group 2 influenza A viruses","volume":"87","author":"Margine","year":"2013","journal-title":"J. Virol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e03617-20","DOI":"10.1128\/mBio.03617-20","article-title":"Mutations in the Hemagglutinin Stalk Domain Do Not Permit Escape from a Protective, Stalk-Based Vaccine-Induced Immune Response in the Mouse Model","volume":"12","author":"Roubidoux","year":"2021","journal-title":"MBio"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1186\/s12934-021-01584-5","article-title":"Immune response induced by oral administration with a Saccharomyces cerevisiae-based SARS-CoV-2 vaccine in mice","volume":"20","author":"Gao","year":"2021","journal-title":"Microb. Cell Fact."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1038\/s41577-020-0311-8","article-title":"The trinity of COVID-19: Immunity, inflammation and intervention","volume":"20","author":"Tay","year":"2020","journal-title":"Nat. Rev. Immunol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1186\/s12951-021-00806-7","article-title":"Virus-like particles: Preparation, immunogenicity and their roles as nanovaccines and drug nanocarriers","volume":"19","author":"Nooraei","year":"2021","journal-title":"J. Nanobiotechnol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1038\/s41577-019-0143-6","article-title":"The human antibody response to influenza A virus infection and vaccination","volume":"19","author":"Krammer","year":"2019","journal-title":"Nat. Rev. Immunol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2605","DOI":"10.4049\/jimmunol.2001420","article-title":"Evaluation of Cellular and Serological Responses to Acute SARS-CoV-2 Infection Demonstrates the Functional Importance of the Receptor-Binding Domain","volume":"206","author":"Mantus","year":"2021","journal-title":"J. Immunol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1038\/s41586-020-2180-5","article-title":"Structure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor","volume":"581","author":"Lan","year":"2020","journal-title":"Nature"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1038\/s41586-020-2380-z","article-title":"Human neutralizing antibodies elicited by SARS-CoV-2 infection","volume":"584","author":"Ju","year":"2020","journal-title":"Nature"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"53","DOI":"10.4161\/mabs.2.1.10788","article-title":"Neutralizing epitopes of the SARS-CoV S-protein cluster independent of repertoire, antigen structure or mAb technology","volume":"2","author":"Berry","year":"2010","journal-title":"MAbs"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1356","DOI":"10.1001\/jamainternmed.2020.4616","article-title":"Evaluating the Association of Clinical Characteristics With Neutralizing Antibody Levels in Patients Who Have Recovered From Mild COVID-19 in Shanghai, China","volume":"180","author":"Wu","year":"2020","journal-title":"JAMA Intern. Med."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Ding, S., Laumaea, A., Benlarbi, M., Beaudoin-Bussi\u00e8res, G., Gasser, R., Medjahed, H., Pancera, M., Stamatatos, L., McGuire, A.T., and Bazin, R. (2020). Antibody Binding to SARS-CoV-2 S Glycoprotein Correlates with but Does Not Predict Neutralization. Viruses, 12.","DOI":"10.1101\/2020.09.08.287482"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1858","DOI":"10.1016\/j.cell.2021.02.010","article-title":"Seasonal human coronavirus antibodies are boosted upon SARS-CoV-2 infection but not associated with protection","volume":"184","author":"Anderson","year":"2021","journal-title":"Cell"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1056","DOI":"10.1016\/j.bbrc.2009.10.115","article-title":"Antibody-mediated synergy and interference in the neutralization of SARS-CoV at an epitope cluster on the spike protein","volume":"390","author":"Zhong","year":"2009","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"664","DOI":"10.1080\/22221751.2020.1742076","article-title":"Generation of neutralizing and non-neutralizing monoclonal antibodies against H7N9 influenza virus","volume":"9","author":"Yang","year":"2020","journal-title":"Emerg. Microbes Infect."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"e01696-18","DOI":"10.1128\/JVI.01696-18","article-title":"Broadly Cross-Reactive, Nonneutralizing Antibodies against Influenza B Virus Hemagglutinin Demonstrate Effector Function-Dependent Protection against Lethal Viral Challenge in Mice","volume":"93","author":"Ioannou","year":"2019","journal-title":"J. Virol."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Martinez, M.E., Capella Gonzalez, C., Huey, D., Peeples, M.E., McCarty, D., and Niewiesk, S. (2021). Immunogenicity and inflammatory properties of respiratory syncytial virus attachment G protein in cotton rats. PLoS ONE, 16.","DOI":"10.1371\/journal.pone.0246770"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1893426","DOI":"10.1080\/19420862.2021.1893426","article-title":"Bispecific VH\/Fab antibodies targeting neutralizing and non-neutralizing Spike epitopes demonstrate enhanced potency against SARS-CoV-2","volume":"13","author":"Lim","year":"2021","journal-title":"MAbs"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"16007","DOI":"10.1038\/mto.2016.7","article-title":"A multi-antigen vaccine in combination with an immunotoxin targeting tumor-associated fibroblast for treating murine melanoma","volume":"3","author":"Fang","year":"2016","journal-title":"Mol. Ther. Oncolytics"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2057","DOI":"10.4049\/jimmunol.1701088","article-title":"Simultaneous Targeting of Multiple Hemagglutinins to APCs for Induction of Broad Immunity against Influenza","volume":"200","author":"Anderson","year":"2018","journal-title":"J. Immunol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.3389\/fmicb.2018.01195","article-title":"An Improved Tobacco Mosaic Virus (TMV)-Conjugated Multiantigen Subunit Vaccine Against Respiratory Tularemia","volume":"9","author":"Mansour","year":"2018","journal-title":"Front. Microbiol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1038\/s41385-020-00340-z","article-title":"Animal and translational models of SARS-CoV-2 infection and COVID-19","volume":"13","author":"Johansen","year":"2020","journal-title":"Mucosal Immunol."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1016\/j.chom.2020.03.023","article-title":"Infection and Rapid Transmission of SARS-CoV-2 in Ferrets","volume":"27","author":"Kim","year":"2020","journal-title":"Cell Host Microbe"}],"container-title":["Vaccines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-393X\/9\/8\/920\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:46:26Z","timestamp":1760165186000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-393X\/9\/8\/920"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,18]]},"references-count":53,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["vaccines9080920"],"URL":"https:\/\/doi.org\/10.3390\/vaccines9080920","relation":{},"ISSN":["2076-393X"],"issn-type":[{"value":"2076-393X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,18]]}}}