{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T19:01:38Z","timestamp":1769799698568,"version":"3.49.0"},"reference-count":41,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T00:00:00Z","timestamp":1769731200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>The emergence of new SARS-CoV-2 variants with immune evasion capabilities underscores the importance of developing a broad-spectrum and effective vaccine. The receptor binding domain (RBD) of the Spike protein has been widely utilized in vaccine due to its high immunogenicity. However, the Spike protein, particularly the RBD region, exhibits significant variability in the evolution of SARS-CoV-2, leading to viral immune evasion and reduced vaccine effectiveness.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A broad-spectrum antigen (M5-RBD) was developed via mutation patching, incorporating key high-impact mutation sites (K417T, L452R, T478K, E484K, N501Y). Additionally, extra mutations (N440K or G446S) were introduced into M5-RBD to evaluate their impact on immune response. M5-RBD was further combined with a novel CpG adjuvant HP007 for immunization.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>M5-RBD elicited high titers of broad-spectrum neutralizing antibodies against SARS-CoV-2 wild-type and various variants (Delta, Omicron BA.1, BA.2, BA.2.75, BA.5, BF.7, BQ.1.1, XBB, EG.5, JN.1, KP.3 strains). Introduction of N440K or G446S significantly diminished the immune response to viral strains. When combined with HP007 adjuvant, M5-RBD induced efficient and durable T cell responses, providing protection to K18-hACE2 KI mice against lethal infections with both wild-type and Omicron BA.2 strains.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>Rationally designed with key high-impact mutation sites, M5-RBD effectively overcomes SARS-CoV-2 variant immune evasion and elicits broad-spectrum neutralizing antibodies. The combination with HP007 adjuvant enhances immune protection, providing a promising strategy for the development of next-generation COVID-19 vaccines.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fcimb.2025.1690554","type":"journal-article","created":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T07:17:58Z","timestamp":1769757478000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["A broad-spectrum SARS-CoV-2 RBD vaccine with selected high-impact mutations and novel adjuvant induces durable T cell response and broad protection in mice"],"prefix":"10.3389","volume":"15","author":[{"given":"Xianying","family":"Chen","sequence":"first","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuzhen","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shimin","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yan","family":"Chen","sequence":"additional","affiliation":[{"name":"Jiangsu Taipure Biopharmaceuticals Co., Ltd.","place":["Taizhou, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shengnan","family":"Qian","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhen","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qianyun","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chengbao","family":"Ma","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Weiyi","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiangpeng","family":"Feng","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiejie","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ming","family":"Guo","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhixiang","family":"Huang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xin","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jie","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haiyan","family":"Zhao","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huan","family":"Yan","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ke","family":"Lan","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Li","family":"Zhou","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Virology and Biosafety, Animal Bio-safety Level III Laboratory, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,1,30]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1002\/mco2.239","article-title":"The rapid rise of SARS-CoV-2 Omicron subvariants with immune evasion properties: XBB.1.5 and BQ.1.1 subvariants","volume":"4","author":"Ao","year":"2023","journal-title":"MedComm (2020)"},{"key":"B2","doi-asserted-by":"publisher","first-page":"9804","DOI":"10.1073\/pnas.0403492101","article-title":"Contributions of the structural proteins of severe acute respiratory syndrome coronavirus to protective immunity","volume":"101","author":"Buchholz","year":"2004","journal-title":"Proc. Natl. Acad. Sci. U.S.A."},{"key":"B3","doi-asserted-by":"publisher","first-page":"657","DOI":"10.1038\/s41586-021-04385-3","article-title":"Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies","volume":"602","author":"Cao","year":"2022","journal-title":"Nature"},{"key":"B4","doi-asserted-by":"publisher","first-page":"142","DOI":"10.1038\/s41586-021-03471-w","article-title":"Escape of SARS-CoV-2 501Y.V2 from neutralization by convalescent plasma","volume":"593","author":"Cele","year":"2021","journal-title":"Nature"},{"key":"B5","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1016\/j.bsheal.2023.02.002","article-title":"Rapid evaluation of heterologous chimeric RBD-dimer mRNA vaccine for currently-epidemic Omicron sub-variants as booster shot after inactivated vaccine","volume":"5","author":"Chen","year":"2023","journal-title":"Biosaf Health"},{"key":"B6","doi-asserted-by":"publisher","first-page":"418","DOI":"10.1002\/jmv.25681","article-title":"Emerging coronaviruses: Genome structure, replication, and pathogenesis","volume":"92","author":"Chen","year":"2020","journal-title":"J. Med. Virol."},{"key":"B7","doi-asserted-by":"publisher","first-page":"100029","DOI":"10.1016\/j.cellin.2022.100029","article-title":"Emerging SARS-CoV-2 variants: Why, how, and what\u2019s next","volume":"1","author":"Chen","year":"2022","journal-title":"Cell Insight"},{"key":"B8","doi-asserted-by":"publisher","first-page":"112","DOI":"10.1038\/s41579-022-00809-7","article-title":"SARS-CoV-2 variant evasion of monoclonal antibodies based on in vitro studies","volume":"21","author":"Cox","year":"2023","journal-title":"Nat. Rev. Microbiol."},{"key":"B9","doi-asserted-by":"crossref","first-page":"eabg3055","DOI":"10.1126\/science.abg3055","article-title":"Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England","volume":"372","author":"Davies","year":"2021","journal-title":"Science"},{"key":"B10","doi-asserted-by":"publisher","first-page":"1556","DOI":"10.1016\/j.cell.2022.03.038","article-title":"mRNA-1273 or mRNA-Omicron boost in vaccinated macaques elicits similar B cell expansion, neutralizing responses, and protection from Omicron","volume":"185","author":"Gagne","year":"2022","journal-title":"Cell"},{"key":"B11","doi-asserted-by":"publisher","first-page":"687","DOI":"10.1038\/s41586-022-04441-6","article-title":"SARS-CoV-2 Omicron virus causes attenuated disease in mice and hamsters","volume":"603","author":"Halfmann","year":"2022","journal-title":"Nature"},{"key":"B12","doi-asserted-by":"publisher","first-page":"2384","DOI":"10.1016\/j.cell.2021.03.036","article-title":"SARS-CoV-2 variants B.1.351 and P.1 escape from neutralizing antibodies","volume":"184","author":"Hoffmann","year":"2021","journal-title":"Cell"},{"key":"B13","doi-asserted-by":"publisher","first-page":"715","DOI":"10.1038\/s41586-022-04479-6","article-title":"SARS-CoV-2 Omicron variant replication in human bronchus and lung ex vivo","volume":"603","author":"Hui","year":"2022","journal-title":"Nature"},{"key":"B14","doi-asserted-by":"publisher","first-page":"615","DOI":"10.1038\/s41577-020-00434-6","article-title":"Immunological considerations for COVID-19 vaccine strategies","volume":"20","author":"Jeyanathan","year":"2020","journal-title":"Nat. Rev. Immunol."},{"key":"B15","doi-asserted-by":"publisher","first-page":"5534","DOI":"10.3390\/ijms23105534","article-title":"Complex mutation pattern of omicron BA.2: evading antibodies without losing receptor interactions","volume":"23","author":"Kannan","year":"2022","journal-title":"Int. J. Mol. Sci."},{"key":"B16","doi-asserted-by":"publisher","first-page":"516","DOI":"10.1038\/s41586-020-2798-3","article-title":"SARS-CoV-2 vaccines in development","volume":"586","author":"Krammer","year":"2020","journal-title":"Nature"},{"key":"B17","doi-asserted-by":"publisher","first-page":"e130","DOI":"10.1002\/mco2.130","article-title":"Antigenicity comparison of SARS-CoV-2 Omicron sublineages with other variants contained multiple mutations in RBD","volume":"3","author":"Li","year":"2022","journal-title":"MedComm (2020)"},{"key":"B18","doi-asserted-by":"publisher","first-page":"100181","DOI":"10.1016\/j.xinn.2021.100181","article-title":"Antibody neutralization to SARS-CoV-2 and variants after 1 year in Wuhan, China","volume":"3","author":"Liu","year":"2022","journal-title":"Innovation (N Y)"},{"key":"B19","doi-asserted-by":"publisher","first-page":"282","DOI":"10.1038\/s41392-020-00402-5","article-title":"RBD-Fc-based COVID-19 vaccine candidate induces highly potent SARS-CoV-2 neutralizing antibody response","volume":"5","author":"Liu","year":"2020","journal-title":"Signal Transduct Target Ther."},{"key":"B20","doi-asserted-by":"publisher","first-page":"269","DOI":"10.1038\/s41422-022-00612-2","article-title":"A novel STING agonist-adjuvanted pan-sarbecovirus vaccine elicits potent and durable neutralizing antibody and T cell responses in mice, rabbits and NHPs","volume":"32","author":"Liu","year":"2022","journal-title":"Cell Res."},{"key":"B21","doi-asserted-by":"publisher","first-page":"567","DOI":"10.1080\/22221751.2022.2031311","article-title":"Drastic decline in sera neutralization against SARS-CoV-2 Omicron variant in Wuhan COVID-19 convalescents","volume":"11","author":"Ma","year":"2022","journal-title":"Emerg. Microbes Infect."},{"key":"B22","doi-asserted-by":"publisher","first-page":"3699","DOI":"10.1038\/s41596-020-0394-5","article-title":"Quantification of SARS-CoV-2 neutralizing antibody by a pseudotyped virus-based assay","volume":"15","author":"Nie","year":"2020","journal-title":"Nat. Protoc."},{"key":"B23","doi-asserted-by":"publisher","first-page":"2116","DOI":"10.1016\/j.cell.2022.05.014","article-title":"Potent cross-reactive antibodies following Omicron breakthrough in vaccinees","volume":"185","author":"Nutalai","year":"2022","journal-title":"Cell"},{"key":"B24","doi-asserted-by":"publisher","first-page":"1024","DOI":"10.1016\/j.cell.2020.09.037","article-title":"Mapping neutralizing and immunodominant sites on the SARS-coV-2 spike receptor-binding domain by structure-guided high-resolution serology","volume":"183","author":"Piccoli","year":"2020","journal-title":"Cell"},{"key":"B25","doi-asserted-by":"publisher","first-page":"1295","DOI":"10.1016\/j.cell.2020.08.012","article-title":"Deep mutational scanning of SARS-coV-2 receptor binding domain reveals constraints on folding and ACE2 binding","volume":"182","author":"Starr","year":"2020","journal-title":"Cell"},{"key":"B26","doi-asserted-by":"publisher","first-page":"1011","DOI":"10.1038\/s41422-021-00531-8","article-title":"Interferon-armed RBD dimer enhances the immunogenicity of RBD for sterilizing immunity against SARS-CoV-2","volume":"31","author":"Sun","year":"2021","journal-title":"Cell Res."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1070","DOI":"10.1038\/s41423-021-00658-z","article-title":"Recombinant vaccine containing an RBD-Fc fusion induced protection against SARS-CoV-2 in nonhuman primates and mice","volume":"18","author":"Sun","year":"2021","journal-title":"Cell Mol. Immunol."},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1038\/d41586-022-00003-y","article-title":"Omicron-targeted vaccines do no better than original jabs in early tests","author":"Waltz","year":"2022","journal-title":"Nature"},{"key":"B29","doi-asserted-by":"publisher","first-page":"603","DOI":"10.1038\/s41586-022-05053-w","article-title":"Antibody evasion by SARS-CoV-2 Omicron subvariants BA.2.12.1, BA.4 and BA.5","volume":"608","author":"Wang","year":"2022","journal-title":"Nature"},{"key":"B30","doi-asserted-by":"publisher","first-page":"130","DOI":"10.1038\/s41586-021-03398-2","article-title":"Antibody resistance of SARS-CoV-2 variants B.1.351 and B.1.1.7","volume":"593","author":"Wang","year":"2021","journal-title":"Nature"},{"key":"B31","doi-asserted-by":"publisher","first-page":"7394","DOI":"10.1016\/j.vaccine.2021.11.001","article-title":"Variant SARS-CoV-2 mRNA vaccines confer broad neutralization as primary or booster series in mice","volume":"39","author":"Wu","year":"2021","journal-title":"Vaccine"},{"key":"B32","doi-asserted-by":"publisher","first-page":"eabg1143","DOI":"10.1126\/scitranslmed.abg1143","article-title":"A recombinant spike protein subunit vaccine confers protective immunity against SARS-CoV-2 infection and transmission in hamsters","volume":"13","author":"Wu","year":"2021","journal-title":"Sci. Transl. Med."},{"key":"B33","doi-asserted-by":"publisher","first-page":"1732","DOI":"10.1016\/j.chom.2022.10.011","article-title":"Lineage-mosaic and mutation-patched spike proteins for broad-spectrum COVID-19 vaccine","volume":"30","author":"Wu","year":"2022","journal-title":"Cell Host Microbe"},{"key":"B34","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2022.04.029","article-title":"Protective prototype-Beta and Delta-Omicron chimeric RBD-dimer vaccines against SARS-CoV-2","volume":"185","author":"Xu","year":"2022","journal-title":"Cell"},{"key":"B35","doi-asserted-by":"publisher","first-page":"572","DOI":"10.1038\/s41586-020-2599-8","article-title":"A vaccine targeting the RBD of the S protein of SARS-CoV-2 induces protective immunity","volume":"586","author":"Yang","year":"2020","journal-title":"Nature"},{"key":"B36","doi-asserted-by":"publisher","DOI":"10.1126\/scitranslmed.abm3302","article-title":"Protective activity of mRNA vaccines against ancestral and variant SARS-CoV-2 strains","volume":"14","author":"Ying","year":"2022","journal-title":"Sci. Transl. Med."},{"key":"B37","doi-asserted-by":"publisher","first-page":"148","DOI":"10.1038\/s41586-023-06753-7","article-title":"Repeated Omicron exposures override ancestral SARS-CoV-2 immune imprinting","volume":"625","author":"Yisimayi","year":"2024","journal-title":"Nature"},{"key":"B38","doi-asserted-by":"publisher","DOI":"10.1080\/22221751.2022.2164219","article-title":"The role of SARS-CoV-2 nucleocapsid protein in antiviral immunity and vaccine development","volume":"12","author":"Yu","year":"2023","journal-title":"Emerg. Microbes Infect."},{"key":"B39","doi-asserted-by":"publisher","first-page":"100","DOI":"10.1038\/s41541-025-01155-4","article-title":"An RBD-Fc mucosal vaccine provides variant-proof protection against SARS-CoV-2 in mice and hamsters","volume":"10","author":"Zhang","year":"2025","journal-title":"NPJ Vaccines"},{"key":"B40","doi-asserted-by":"publisher","first-page":"2353302","DOI":"10.1080\/22221751.2024.2353302","article-title":"The lethal K18-hACE2 knock-in mouse model mimicking the severe pneumonia of COVID-19 is practicable for antiviral development","volume":"13","author":"Zhang","year":"2024","journal-title":"Emerg. Microbes Infect."},{"key":"B41","doi-asserted-by":"publisher","first-page":"551","DOI":"10.1016\/j.chom.2021.02.019","article-title":"Robust SARS-CoV-2 infection in nasal turbinates after treatment with systemic neutralizing antibodies","volume":"29","author":"Zhou","year":"2021","journal-title":"Cell Host Microbe"}],"container-title":["Frontiers in Cellular and Infection Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcimb.2025.1690554\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T07:17:59Z","timestamp":1769757479000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcimb.2025.1690554\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,30]]},"references-count":41,"alternative-id":["10.3389\/fcimb.2025.1690554"],"URL":"https:\/\/doi.org\/10.3389\/fcimb.2025.1690554","relation":{},"ISSN":["2235-2988"],"issn-type":[{"value":"2235-2988","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,30]]},"article-number":"1690554"}}