Kwiatkowski Alexander J, Schulman Jacob A, Pagendarm Hayden M, Pastora Lucinda E, Tossberg John T, Zhang Ruilin, Chada Neil C, Woodruff Mia E, Sheehy Taylor L, Arora Karan, Karijolich John, Aune Thomas M, Wilson John T
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
ACS Appl Mater Interfaces. 2025 Aug 28. doi: 10.1021/acsami.5c16047.
Vaccine adjuvants stimulate innate immunity to enhance and shape adaptive immune responses. However, approved adjuvants typically elicit weak CD8 T cell responses to protein- and peptide-based vaccines, motivating an investigation into the discovery and testing of new adjuvants. Unedited forms of endogenous Alu RNAs are sensed by pattern recognition receptors (PRRs) to trigger sterile inflammation, and therefore we hypothesized that synthetic Alu RNA molecules could be harnessed as vaccine adjuvants. To enhance their intracellular delivery, Alu RNA was copackaged with a model antigen into polymer nanoparticles that promoted endosomal escape of Alu RNA to the cytosol. Using this nanovaccine formulation, we found that Alu RNA activated antigen-presenting cells in vitro and in vaccine-site draining lymph nodes in vivo. Furthermore, we demonstrated that vaccine formulations containing Alu RNA as an adjuvant elicited comparable CD8 T cell responses to those containing the common but highly heterogeneous RNA adjuvant PolyIC, and that this response protected mice from tumor challenge. Based on this, we further evaluated the antitumor efficacy of nanovaccine formulations containing Alu RNA adjuvants in mice with established tumors, again observing comparable responses to formulations containing PolyIC. Finally, we found that nanovaccines adjuvanted with Alu RNA could improve responses to anti-PD-1 immune checkpoint blockade in tumor-bearing mice. Overall, this study demonstrates that unedited Alu RNA coformulated with antigen in polymer nanoparticles can be harnessed as an effective vaccine adjuvant for stimulating CD8 T cell responses with antitumor function and may offer a sequence-defined alternative to PolyIC.
疫苗佐剂刺激天然免疫以增强和塑造适应性免疫反应。然而，已获批的佐剂通常对基于蛋白质和肽的疫苗引发较弱的CD8 T细胞反应，这促使人们对新型佐剂的发现和测试展开研究。内源性Alu RNA的未编辑形式可被模式识别受体（PRR）识别以触发无菌性炎症，因此我们推测合成的Alu RNA分子可被用作疫苗佐剂。为了增强其细胞内递送，Alu RNA与一种模型抗原共同包装到聚合物纳米颗粒中，该纳米颗粒促进Alu RNA从内体逃逸到细胞质中。使用这种纳米疫苗制剂，我们发现Alu RNA在体外和体内疫苗接种部位引流淋巴结中激活了抗原呈递细胞。此外，我们证明，含有Alu RNA作为佐剂的疫苗制剂引发的CD8 T细胞反应与含有常见但高度异质的RNA佐剂PolyIC的制剂相当，并且这种反应保护小鼠免受肿瘤攻击。基于此，我们进一步评估了含有Alu RNA佐剂的纳米疫苗制剂在已建立肿瘤的小鼠中的抗肿瘤功效，再次观察到与含有PolyIC的制剂相当的反应。最后，我们发现用Alu RNA佐剂的纳米疫苗可以改善荷瘤小鼠对抗PD-1免疫检查点阻断的反应。总体而言，这项研究表明，与抗原在聚合物纳米颗粒中共配制的未编辑Alu RNA可作为一种有效的疫苗佐剂，用于刺激具有抗肿瘤功能的CD8 T细胞反应，并可能为PolyIC提供一种序列定义的替代物。
