{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,30]],"date-time":"2025-09-30T00:05:38Z","timestamp":1759190738537,"version":"3.44.0"},"reference-count":50,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,9,28]],"date-time":"2025-09-28T00:00:00Z","timestamp":1759017600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R01 AI132212","R01 AI168048","HHS-NIH-NIAID-BAA2017"],"award-info":[{"award-number":["R01 AI132212","R01 AI168048","HHS-NIH-NIAID-BAA2017"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: The quest for well-defined immunoadjuvants remains one of the highest priorities for the successful development of effective vaccines. Combination adjuvants, which are designed to integrate both the ability to activate a variety of immune mechanisms and synergistically improve the delivery of vaccine components, are well-positioned to address the unmet needs. The development of a preventive vaccine against hepatitis C virus (HCV)\u2014a major public health concern\u2014is a particular instance in which the choice of the immunoadjuvant is of utmost importance. Methods: We assembled a lipid A Toll-like receptor 4 (TLR4) agonist BECC438 and TLR7\/8 agonist resiquimod (R848) on a polyphosphazene macromolecule (PCPP) to create a nanoscale immunoadjuvant-vaccine delivery system: PCPP-R+BECC438. This aqueous-based system was formulated with the HCV sE2 antigen, and the resulting vaccine candidate was evaluated in vivo for the ability to induce immune responses. Results: Co-assembly of adjuvants resulted in a visually clear aqueous system of nanoscale dimensions, monomodal size distribution, and entropy-driven interactions between components. Intramuscular immunization of mice with HCV sE2 antigen formulated in a polyphosphazene-based nano-system induced ten-fold higher IgG and IgG2a titers than the antigen adjuvanted with BECC438 alone. PCPP-R+BECC438 formulated HCV sE2 also produced statistically significant improvements in IgG2a\/IgG1 ratio and more robust HCVpp neutralization ID50 titers than control formulations. Conclusions: Polyphosphazene-assembled adjuvant nano-system promotes in vivo immune responses of enhanced quantity and quality of antibodies with increased potency of HCV neutralization.<\/jats:p>","DOI":"10.3390\/vaccines13101012","type":"journal-article","created":{"date-parts":[[2025,9,29]],"date-time":"2025-09-29T08:00:32Z","timestamp":1759132832000},"page":"1012","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Polyphosphazene-Mediated Assembly of TLR4 and TLR7\/8 Agonists Enables a Potent Nano-Adjuvant Delivery System for Hepatitis C Virus Vaccine Antigens"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6186-6156","authenticated-orcid":false,"given":"Alexander K.","family":"Andrianov","sequence":"first","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alexander","family":"Marin","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah","family":"Jeong","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Liudmila","family":"Kulakova","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ananda","family":"Chowdhury","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3969-5404","authenticated-orcid":false,"given":"Raman","family":"Hlushko","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sayan","family":"Das","sequence":"additional","affiliation":[{"name":"Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesca","family":"Moy","sequence":"additional","affiliation":[{"name":"Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0766-5131","authenticated-orcid":false,"given":"Eric A.","family":"Toth","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5016-8694","authenticated-orcid":false,"given":"Robert K.","family":"Ernst","sequence":"additional","affiliation":[{"name":"Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9766-9995","authenticated-orcid":false,"given":"Thomas R.","family":"Fuerst","sequence":"additional","affiliation":[{"name":"Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA"},{"name":"Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1597","DOI":"10.1038\/nm.3409","article-title":"Key roles of adjuvants in modern vaccines","volume":"19","author":"Reed","year":"2013","journal-title":"Nat. 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