Integration of TLR7/8 agonists into lipid nanoparticles enhances antigen-specific immune responses to N1-methyl-Ψ-modified mRNA-LNP vaccines
Year: 2025
Type: article
Abstract: N1-methylpseudouridine (N1-methyl-Ψ)-modified mRNA offers a safer alternative to unmodified mRNA-based cancer immunotherapies but induces weaker innate immune responses. This study aimed to enhance the expression of N1-methyl-Ψ-modified mRNA and improve innate and adaptive immune responses by incorporating a toll-like receptor (TLR) 7/8 agonist (AD7/8) into a lipid nanoparticle (LNP). AD7/8 was incorporated into LNPs by partially replacing cholesterol, and the mRNA expression efficiency of various formulations was evaluated, leading to the selection of the LNP formulation containing 0.5% AD7/8 (AD03-LNP). AD03-LNP was evaluated using mRNAs encoding human papillomavirus (HPV)16 E7 and HPV18 E6 antigens, the SARS-CoV-2 Omicron spike protein (S-Omicron), and influenza hemagglutinin (HA), and it consistently enhanced antigen-specific immune responses compared with conventional LNP. In the HPV mRNA model, antigen-specific CD8⁺ T cell and cytokine responses were significantly increased by 1.5-2.1-fold. In the S-Omicron mRNA model, IgG2a levels, indicative of a Th1-skewed response, were markedly elevated by 8-fold as measured by endpoint titers. Importantly, in the HA mRNA model, which evaluated both cellular and humoral immunity, AD03-LNP induced significantly higher CD8⁺ T cell responses by 2.3-2.6-fold, together with increased antibody production, with total IgG elevated by 3.6-fold as measured by endpoint titers. These findings demonstrate that AD03-LNP enhances both cellular and humoral immune responses across diverse antigens. These results provide insights into how TLR7/8 agonist-loaded LNPs influence mRNA expression and immune responses, supporting an effective formulation approach to boost the immunogenicity of mRNA-LNP vaccines. This approach may help advance the design of mRNA-based cancer immunotherapies and prophylactic vaccines that depend on strong T cell responses.
Authors: Huijeong Choi, Seonghyun Lee, Hyejin Kim, Seo-Hyeon Bae, Sohee Jo, Jungmin Kim, Yeeun Lee, Dahyeon Ha, Ayoung Oh, Subin Yoon, Sanghyuk Jeon, Yu-Sun Lee, Youngran Cho, Seongje Cho, Gahyun Roh, Sowon Lee, Jayaraj Gowda, Hyo-Jung Park, Jisun Lee, Daesub Song, So-Hee Hong, Soo Bong Han, Jae-Hwan Nam
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,890
Funders: Ministry of Food and Drug Safety, Ministry of Agriculture, Food and Rural Affairs, Ministry of Health and Welfare, Korea Research Institute of Chemical Technology, Korea Health Industry Development Institute, Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry
OpenAlex ID: W4416538688