{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T18:33:06Z","timestamp":1777660386207,"version":"3.51.4"},"reference-count":44,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,6,16]],"date-time":"2020-06-16T00:00:00Z","timestamp":1592265600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003715","name":"Korea Research Institute of Bioscience and Biotechnology","doi-asserted-by":"publisher","award":["KGM9942011"],"award-info":[{"award-number":["KGM9942011"]}],"id":[{"id":"10.13039\/501100003715","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003661","name":"Korea Institute for Advancement of Technology","doi-asserted-by":"publisher","award":["P0006222"],"award-info":[{"award-number":["P0006222"]}],"id":[{"id":"10.13039\/501100003661","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Emerging influenza viruses pose an extreme global risk to human health, resulting in an urgent need for effective vaccination against influenza infection. Adjuvants are vital components that can improve vaccine efficacy, yet only a few adjuvants have been licensed in human vaccines. Here, we investigate the adjuvant effects of Escherichia coli-produced monophosphoryl lipid A (MPL), named EcML, in enhancing the immunogenicity and efficacy of an influenza vaccine. Similar to MPL, EcML activated dendritic cells and enhanced the antigen processing of cells in vitro. Using ovalbumin (OVA) as a model antigen, EcML increased OVA-specific antibody production, cytotoxic T lymphocyte activity. The safety of EcML was demonstrated as being similar to that of MPL by showing not significant in vitro cell cytotoxicity but transient systemic inflammatory responses within 24 h in OVA immunized mice. Importantly, mice vaccinated with pandemic H1N1 (pH1N1) vaccine antigen, combined with EcML, were fully protected from pH1N1 virus infection by enhanced influenza-specific antibody titers, hemagglutination inhibition titers, and IFN-\u03b3- secreting cells. Taken together, our results strongly suggest that EcML might be a promising vaccine adjuvant for preventing influenza virus infection.<\/jats:p>","DOI":"10.3390\/vaccines8020306","type":"journal-article","created":{"date-parts":[[2020,6,16]],"date-time":"2020-06-16T13:20:43Z","timestamp":1592313643000},"page":"306","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["E. coli-Produced Monophosphoryl Lipid a Significantly Enhances Protective Immunity of Pandemic H1N1 Vaccine"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3451-0493","authenticated-orcid":false,"given":"Quyen Thi","family":"Nguyen","sequence":"first","affiliation":[{"name":"Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea"},{"name":"Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eunjin","family":"Kim","sequence":"additional","affiliation":[{"name":"Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea"},{"name":"College of Veterinary Medicine, Chungnam National University, Daejeon 34134, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1935-8542","authenticated-orcid":false,"given":"Jihyun","family":"Yang","sequence":"additional","affiliation":[{"name":"Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chankyu","family":"Lee","sequence":"additional","affiliation":[{"name":"Eubiologics. Co., Ltd., V Plant, Gangwon-do 24410, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Da Hui","family":"Ha","sequence":"additional","affiliation":[{"name":"Eubiologics. Co., Ltd., V Plant, Gangwon-do 24410, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Choon Geun","family":"Lee","sequence":"additional","affiliation":[{"name":"Eubiologics. Co., Ltd., V Plant, Gangwon-do 24410, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ye Ram","family":"Lee","sequence":"additional","affiliation":[{"name":"Eubiologics. Co., Ltd., V Plant, Gangwon-do 24410, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haryoung","family":"Poo","sequence":"additional","affiliation":[{"name":"Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea"},{"name":"Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon 34113, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1044","DOI":"10.1016\/j.celrep.2013.03.034","article-title":"Neuraminidase-mediated, nkp46-dependent immune-evasion mechanism of influenza viruses","volume":"3","author":"Glasner","year":"2013","journal-title":"Cell Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1093\/oxfordjournals.epirev.a017917","article-title":"Emerging infections: Pandemic influenza","volume":"18","author":"Glezen","year":"1996","journal-title":"Epidemiol. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1016\/S1473-3099(12)70121-4","article-title":"Estimated global mortality associated with the first 12 months of 2009 pandemic influenza a h1n1 virus circulation: A modelling study","volume":"12","author":"Dawood","year":"2012","journal-title":"Lancet Infect. Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"550","DOI":"10.1080\/21645515.2017.1415684","article-title":"Adjuvanted influenza vaccines","volume":"14","author":"Tregoning","year":"2018","journal-title":"Hum. Vaccines Immunother."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1038\/nri2510","article-title":"Towards an understanding of the adjuvant action of aluminium","volume":"9","author":"Marrack","year":"2009","journal-title":"Nat. Rev. Immunol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/j.jsps.2011.06.003","article-title":"Vaccine adjuvants-current status and prospects on controlled release adjuvancity","volume":"19","author":"Sivakumar","year":"2011","journal-title":"Saudi. Pharm. J."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"f794","DOI":"10.1136\/bmj.f794","article-title":"Risk of narcolepsy in children and young people receiving as03 adjuvanted pandemic a\/h1n1 2009 influenza vaccine: Retrospective analysis","volume":"346","author":"Miller","year":"2013","journal-title":"BMJ"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Nohynek, H., Jokinen, J., Partinen, M., Vaarala, O., Kirjavainen, T., Sundman, J., Himanen, S.L., Hublin, C., Julkunen, I., and Olsen, P. (2012). As03 adjuvanted ah1n1 vaccine associated with an abrupt increase in the incidence of childhood narcolepsy in finland. PLoS ONE, 7.","DOI":"10.1371\/journal.pone.0033536"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"621","DOI":"10.1016\/j.bbrc.2009.08.062","article-title":"Toll-like receptors and innate immunity","volume":"388","author":"Kumar","year":"2009","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.coi.2016.06.007","article-title":"The science of vaccine adjuvants: Advances in tlr4 ligand adjuvants","volume":"41","author":"Reed","year":"2016","journal-title":"Curr. Opin. Immunol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e00492-17","DOI":"10.1128\/mBio.00492-17","article-title":"Rationally designed tlr4 ligands for vaccine adjuvant discovery","volume":"8","author":"Gregg","year":"2017","journal-title":"MBio"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"44839","DOI":"10.1038\/srep44839","article-title":"Poly-gamma-glutamic acid\/chitosan nanogel greatly enhances the efficacy and heterosubtypic cross-reactivity of h1n1 pandemic influenza vaccine","volume":"7","author":"Yang","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1604","DOI":"10.3389\/fimmu.2019.01604","article-title":"Poly-gamma-glutamic acid complexed with alum induces cross-protective immunity of pandemic h1n1 vaccine","volume":"10","author":"Nguyen","year":"2019","journal-title":"Front. Immunol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3341","DOI":"10.1016\/j.vaccine.2010.08.002","article-title":"Tlr-based immune adjuvants","volume":"29","author":"Steinhagen","year":"2011","journal-title":"Vaccine"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2161","DOI":"10.1016\/S0140-6736(07)60946-5","article-title":"Efficacy of a prophylactic adjuvanted bivalent l1 virus-like-particle vaccine against infection with human papillomavirus types 16 and 18 in young women: An interim analysis of a phase iii double-blind, randomised controlled trial","volume":"369","author":"Paavonen","year":"2007","journal-title":"Lancet"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1586\/14760584.6.2.133","article-title":"New hepatitis b vaccine formulated with an improved adjuvant system","volume":"6","author":"Kundi","year":"2007","journal-title":"Expert Rev. Vaccines"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1628","DOI":"10.1126\/science.1138963","article-title":"The vaccine adjuvant monophosphoryl lipid a as a trif-biased agonist of tlr4","volume":"316","author":"Cekic","year":"2007","journal-title":"Science"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3231","DOI":"10.1007\/s00018-008-8228-6","article-title":"Putting endotoxin to work for us: Monophosphoryl lipid a as a safe and effective vaccine adjuvant","volume":"65","author":"Casella","year":"2008","journal-title":"Cell Mol. Life Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.smim.2018.10.004","article-title":"Correlates of gla family adjuvants\u2019 activities","volume":"39","author":"Reed","year":"2018","journal-title":"Semin. Immunol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.ymben.2019.11.009","article-title":"Metabolic engineering of escherichia coli to produce a monophosphoryl lipid a adjuvant","volume":"57","author":"Ji","year":"2020","journal-title":"Metab. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1790","DOI":"10.1038\/s41467-020-15569-2","article-title":"Alarmin-painted exosomes elicit persistent antitumor immunity in large established tumors in mice","volume":"11","author":"Zuo","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_22","first-page":"e773","article-title":"Generation of bone marrow derived murine dendritic cells for use in 2-photon imaging","volume":"17","author":"Matheu","year":"2008","journal-title":"J. Vis. Exp."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3281","DOI":"10.1002\/smll.201101836","article-title":"Bioderived polyelectrolyte nanogels for robust antigen loading and vaccine adjuvant effects","volume":"7","author":"Lim","year":"2011","journal-title":"Small"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1146\/annurev-immunol-020711-074950","article-title":"The dendritic cell lineage: Ontogeny and function of dendritic cells and their subsets in the steady state and the inflamed setting","volume":"31","author":"Merad","year":"2013","journal-title":"Annu. Rev. Immunol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1038\/ni1112","article-title":"Toll-like receptor control of the adaptive immune responses","volume":"5","author":"Iwasaki","year":"2004","journal-title":"Nat. Immunol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.canlet.2019.12.012","article-title":"Dendritic cell activation by an e. Coli-derived monophosphoryl lipid a enhances the efficacy of pd-1 blockade","volume":"472","author":"Jeong","year":"2020","journal-title":"Cancer Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"6867","DOI":"10.1038\/sj.onc.1203219","article-title":"How nf-kappab is activated: The role of the ikappab kinase (ikk) complex","volume":"18","author":"Karin","year":"1999","journal-title":"Oncogene"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"326","DOI":"10.4110\/in.2017.17.5.326","article-title":"Distinct effects of monophosphoryl lipid a, oligodeoxynucleotide cpg, and combination adjuvants on modulating innate and adaptive immune responses to influenza vaccination","volume":"17","author":"Ko","year":"2017","journal-title":"Immune Netw."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1002\/9780470035399.ch9","article-title":"Linking innate to adaptive immunity through dendritic cells","volume":"279","author":"Steinman","year":"2006","journal-title":"Novartis Found. Symp."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5402","DOI":"10.4049\/jimmunol.180.8.5402","article-title":"The adjuvants aluminum hydroxide and mf59 induce monocyte and granulocyte chemoattractants and enhance monocyte differentiation toward dendritic cells","volume":"180","author":"Seubert","year":"2008","journal-title":"J. Immunol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1284","DOI":"10.1016\/j.cell.2012.02.012","article-title":"Beyond empiricism: Informing vaccine development through innate immunity research","volume":"148","author":"Levitz","year":"2012","journal-title":"Cell"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"225","DOI":"10.3389\/fimmu.2017.00225","article-title":"Toll-like receptor ligand-based vaccine adjuvants require intact myd88 signaling in antigen-presenting cells for germinal center formation and antibody production","volume":"8","author":"Mosaheb","year":"2017","journal-title":"Front. Immunol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1080\/14760584.2016.1213632","article-title":"Adjuvant system as01: Helping to overcome the challenges of modern vaccines","volume":"16","author":"Didierlaurent","year":"2017","journal-title":"Expert Rev. Vaccines"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"748","DOI":"10.1038\/nm1257","article-title":"Accelerated cd8+ t-cell memory and prime-boost response after dendritic-cell vaccination","volume":"11","author":"Badovinac","year":"2005","journal-title":"Nat. Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"7331","DOI":"10.1016\/j.vaccine.2010.08.075","article-title":"Safety of mf59-adjuvanted versus non-adjuvanted influenza vaccines in children and adolescents: An integrated analysis","volume":"28","author":"Black","year":"2010","journal-title":"Vaccine"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"714","DOI":"10.1016\/j.vaccine.2015.12.024","article-title":"A systematic review and meta-analysis on the safety of newly adjuvanted vaccines among children","volume":"34","author":"Stassijns","year":"2016","journal-title":"Vaccine"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3526","DOI":"10.1038\/s41598-018-22020-6","article-title":"Body temperature measurement in mice during acute illness: Implantable temperature transponder versus surface infrared thermometry","volume":"8","author":"Mei","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Olejnik, J., Hume, A.J., and Muhlberger, E. (2018). Toll-like receptor 4 in acute viral infection: Too much of a good thing. PLoS Pathog., 14.","DOI":"10.1371\/journal.ppat.1007390"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1097","DOI":"10.2217\/imt.14.72","article-title":"Cytokine production associated with smallpox vaccine responses","volume":"6","author":"Simon","year":"2014","journal-title":"Immunotherapy"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3360","DOI":"10.1016\/j.vaccine.2015.05.008","article-title":"Proinflammatory cytokine responses correspond with subjective side effects after influenza virus vaccination","volume":"33","author":"Christian","year":"2015","journal-title":"Vaccine"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.virol.2010.12.016","article-title":"Contributions of humoral and cellular immunity to vaccine-induced protection in humans","volume":"411","author":"Amanna","year":"2011","journal-title":"Virology"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"4575","DOI":"10.1016\/j.vaccine.2007.03.045","article-title":"Activation of dendritic cells and induction of cd4(+) t cell differentiation by aluminum-containing adjuvants","volume":"25","author":"Sokolovska","year":"2007","journal-title":"Vaccine"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1920","DOI":"10.4049\/jimmunol.1400948","article-title":"Enhancement of adaptive immunity by the human vaccine adjuvant as01 depends on activated dendritic cells","volume":"193","author":"Didierlaurent","year":"2014","journal-title":"J. Immunol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"6186","DOI":"10.4049\/jimmunol.0901474","article-title":"As04, an aluminum salt- and tlr4 agonist-based adjuvant system, induces a transient localized innate immune response leading to enhanced adaptive immunity","volume":"183","author":"Didierlaurent","year":"2009","journal-title":"J. Immunol."}],"container-title":["Vaccines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-393X\/8\/2\/306\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:39:26Z","timestamp":1760175566000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-393X\/8\/2\/306"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,16]]},"references-count":44,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2020,6]]}},"alternative-id":["vaccines8020306"],"URL":"https:\/\/doi.org\/10.3390\/vaccines8020306","relation":{},"ISSN":["2076-393X"],"issn-type":[{"value":"2076-393X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,6,16]]}}}