Gnazzo Victoria, Saleh Hanaa, Castro Ítalo A, Boon Adrianus C M, Pinto Amelia K, Brien James D, López Carolina B
Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, USA.
Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, Missouri, USA.
mBio. 2025 Feb 5;16(2):e0358924. doi: 10.1128/mbio.03589-24. Epub 2024 Dec 18.
A challenge in viral vaccine development is to produce vaccines that generate both neutralizing antibodies to prevent infection and cytotoxic CD8 T-cells that target conserved viral proteins and can eliminate infected cells to control virus spread. mRNA technology offers an opportunity to design vaccines based on conserved CD8-targeting epitopes, but achieving robust antigen-specific CD8 T-cells remains a challenge. Here, we tested the viral-derived oligonucleotide DDO268 as an adjuvant in the context of a model influenza A virus (IAV) nucleoprotein (NP) mRNA vaccine in C57BL/6 mice. DDO268 when co-packaged with mRNA in lipid nanoparticles is sensed by RIG I-like receptors and safely induces local type I interferon (IFN) production followed by dendritic cells type 1 activation and migration to the draining lymph nodes. This early response triggered by DDO268 improved the generation of IgG2c antibodies and antigen-specific Th1 CD4 and CD8 T-cells (IFNγTNFαIL2) that provided enhanced protection against lethal IAV challenge. In addition, the inclusion of DDO268 reduced the antigen dose required to achieve protection. These results highlight the potential of DDO268 as an effective mRNA vaccine adjuvant and show that an IAV NP mRNA/DDO268 vaccine is a promising approach for generating protective immunity against conserved internal IAV epitopes.IMPORTANCEVaccines that generate neutralizing antibodies and cytotoxic CD8 T-cells targeting conserved epitopes are ideal for effective protection against viruses. mRNA vaccines combined with the right adjuvant offer a promising solution to this challenge. We show that the virus-derived oligonucleotide DDO268 enhances antibody and T-cell responses to an influenza A virus (IAV) nucleoprotein mRNA vaccine in mice. DDO268 safely induces local type I interferon production and stimulates dendritic cell activation providing enhanced protection against IAV challenge. In addition, the adjuvant activity of DDO268 allows for the use of lower antigen doses during vaccination.
病毒疫苗研发面临的一个挑战是生产出既能产生中和抗体以预防感染，又能产生靶向保守病毒蛋白的细胞毒性CD8 T细胞的疫苗，这些细胞毒性CD8 T细胞能够清除被感染细胞以控制病毒传播。信使核糖核酸（mRNA）技术为基于保守的CD8靶向表位设计疫苗提供了机会，但要实现强大的抗原特异性CD8 T细胞仍然是一项挑战。在此，我们在C57BL/6小鼠的甲型流感病毒（IAV）核蛋白（NP）mRNA疫苗背景下，测试了病毒衍生的寡核苷酸DDO268作为佐剂的效果。当DDO268与mRNA共同包裹在脂质纳米颗粒中时，可被视黄酸诱导基因I样受体识别，并安全地诱导局部I型干扰素（IFN）产生，随后激活1型树突状细胞并迁移至引流淋巴结。DDO268引发的这种早期反应改善了IgG2c抗体以及抗原特异性Th1 CD4和CD8 T细胞（IFNγ、TNFα、IL2）的生成，这些细胞提供了针对致死性IAV攻击的增强保护。此外，添加DDO268降低了实现保护所需的抗原剂量。这些结果凸显了DDO268作为一种有效的mRNA疫苗佐剂的潜力，并表明IAV NP mRNA/DDO268疫苗是针对保守的IAV内部表位产生保护性免疫的一种有前景的方法。重要性能够产生中和抗体和靶向保守表位的细胞毒性CD8 T细胞的疫苗是有效预防病毒感染的理想选择。mRNA疫苗与合适的佐剂相结合为应对这一挑战提供了一个有前景的解决方案。我们表明，病毒衍生的寡核苷酸DDO268可增强小鼠对甲型流感病毒（IAV）核蛋白mRNA疫苗的抗体和T细胞反应。DDO268安全地诱导局部I型干扰素产生并刺激树突状细胞活化，从而提供针对IAV攻击的增强保护。此外，DDO268的佐剂活性允许在疫苗接种期间使用更低的抗原剂量。
