{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T04:46:02Z","timestamp":1785818762826,"version":"3.56.0"},"reference-count":43,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,2]],"date-time":"2026-08-02T00:00:00Z","timestamp":1785628800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002855","name":"Ministry of Science and Technology of the People\u2019s Republic of China","doi-asserted-by":"crossref","award":["2021YFC2302500"],"award-info":[{"award-number":["2021YFC2302500"]}],"id":[{"id":"10.13039\/501100002855","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100002855","name":"Ministry of Science and Technology of the People\u2019s Republic of China","doi-asserted-by":"crossref","award":["2021YFC2302501"],"award-info":[{"award-number":["2021YFC2302501"]}],"id":[{"id":"10.13039\/501100002855","id-type":"DOI","asserted-by":"crossref"}]},{"award":["2021YFC2302500"],"award-info":[{"award-number":["2021YFC2302500"]}],"id":[{"id":"https:\/\/ror.org\/027s68j25","id-type":"ROR","asserted-by":"publisher"}]},{"award":["2021YFC2302501"],"award-info":[{"award-number":["2021YFC2302501"]}],"id":[{"id":"https:\/\/ror.org\/027s68j25","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003399","name":"Shanghai Municipal Science and Technology","doi-asserted-by":"publisher","award":["ZD2021CY001-ZXS006R1-2"],"award-info":[{"award-number":["ZD2021CY001-ZXS006R1-2"]}],"id":[{"id":"10.13039\/501100003399","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Fudan-Advaccine Join-Laboratory Innovation"},{"DOI":"10.13039\/501100008868","name":"Jiangsu Provincial Department of Science and Technology","doi-asserted-by":"crossref","award":["BG2005054"],"award-info":[{"award-number":["BG2005054"]}],"id":[{"id":"10.13039\/501100008868","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: DNA vaccines are widely used due to their low production cost, ease of large-scale manufacturing, and rapid responsiveness to emerging epidemics. However, their relatively modest immunogenicity in larger species often requires potent adjuvants to elicit robust protective responses. GM-CSF and Flt3L are two cytokine adjuvants targeting dendritic cells (DCs). Although their combination has been reported to augment immune responses, the mechanism underlying the complementary effects of a genetically fused GM-CSF-Flt3L adjuvant plasmid remains incompletely understood. Methods: We constructed a GM-CSF-Flt3L fusion adjuvant plasmid and compared it with single-adjuvant plasmids for their effects on innate, humoral, and cellular immunity, as well as protective efficacy against lethal homologous virus challenge. Results: Compared with single-adjuvant plasmids, GM-CSF-Flt3L synergistically promoted the maturation of bone marrow-derived dendritic cells (BMDCs) and activated draining lymph node DCs, differentially expanded DC subsets, and enhanced the recruitment of migratory DCs. This adjuvant significantly elevated hemagglutinin (HA)-specific serum IgG titers, hemagglutination inhibition (HI) titers, and the responses of T follicular helper (TFH) cells and germinal center B (GCB) cells, while also enhancing the capacity of HA-specific CD4+ and CD8+ T cells to secrete IFN-\u03b3 and TNF-\u03b1. Following lethal homologous virus challenge, the GM-CSF-Flt3L group exhibited markedly reduced lung viral loads and no significant pathological damage in lung tissues. Conclusions: These findings demonstrate that the GM-CSF-Flt3L fusion adjuvant complementarily enhances humoral and cellular immune responses induced by the influenza DNA vaccine and improves protective efficacy, highlighting its potential as an effective DNA vaccine adjuvant.<\/jats:p>","DOI":"10.3390\/vaccines14080671","type":"journal-article","created":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T12:57:56Z","timestamp":1785761876000},"page":"671","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A GM-CSF-Flt3L Fused Adjuvant Enhances Immune Responses and Protective Efficacy of Influenza DNA Vaccine in Mice"],"prefix":"10.3390","volume":"14","author":[{"given":"Hongzhe","family":"Lin","sequence":"first","affiliation":[{"name":"Key Laboratory of Medical Molecular Virology (MOE\/NHC\/CAMS) & Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingyue","family":"Chen","sequence":"additional","affiliation":[{"name":"Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rong","family":"Xiang","sequence":"additional","affiliation":[{"name":"Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yating","family":"Kang","sequence":"additional","affiliation":[{"name":"Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yiwei","family":"Zhong","sequence":"additional","affiliation":[{"name":"Key Laboratory of Medical Molecular Virology (MOE\/NHC\/CAMS) & Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China"},{"name":"Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duan","family":"Ma","sequence":"additional","affiliation":[{"name":"Key Laboratory of Medical Molecular Virology (MOE\/NHC\/CAMS) & Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9945-1818","authenticated-orcid":false,"given":"Bin","family":"Wang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Medical Molecular Virology (MOE\/NHC\/CAMS) & Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China"},{"name":"Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China"},{"name":"Advaccine Biopharmaceuticals Suzhou Co., Ltd., Suzhou 215123, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1465","DOI":"10.1126\/science.1690918","article-title":"Direct Gene Transfer into Mouse Muscle in Vivo","volume":"247","author":"Wolff","year":"1990","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"102536","DOI":"10.1016\/j.omtn.2025.102536","article-title":"Genetic Adjuvants: A Paradigm Shift in Vaccine Development and Immune Modulation","volume":"36","author":"Spunde","year":"2025","journal-title":"Mol. 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