Multivalent presentation of ligands often enhances receptor activation and downstream signalling. DNA origami offers a precise nanoscale spacing of ligands, a potentially useful feature for therapeutic nanoparticles. Here we use a square-block DNA origami platform to explore the importance of the spacing of CpG oligonucleotides. CpG engages Toll-like receptors and therefore acts to activate dendritic cells. Through in vitro cell culture studies and in vivo tumour treatment models, we demonstrate that square blocks induce Th1 immune polarization when CpG is spaced at 3.5 nm. We observe that this DNA origami vaccine enhances DC activation, antigen cross-presentation, CD8 T-cell activation, Th1-polarized CD4 activation and natural-killer-cell activation. The vaccine also effectively synergizes with anti-PD-L1 for improved cancer immunotherapy in melanoma and lymphoma models and induces long-term T-cell memory. Our results suggest that DNA origami may serve as a platform for controlling adjuvant spacing and co-delivering antigens in vaccines.

配体的多价呈递通常会增强受体激活和下游信号传导。DNA 折纸提供了精确的纳米级配体间距，这对于治疗性纳米粒子来说是一个潜在有用的特征。在这里，我们使用方块 DNA 折纸平台来探讨 CpG 寡核苷酸间距的重要性。CpG 与 Toll 样受体结合，从而激活树突状细胞。通过体外细胞培养研究和体内肿瘤治疗模型，我们证明当 CpG 间隔为 3.5 nm 时，方形块会诱导 Th1 免疫极化。我们观察到这种 DNA 折纸疫苗增强了 DC 激活、抗原交叉呈递、CD8 T 细胞激活、Th1 极化 CD4 激活和自然杀伤细胞激活。该疫苗还可以有效地与抗 PD-L1 协同作用，改善黑色素瘤和淋巴瘤模型中的癌症免疫治疗，并诱导长期 T 细胞记忆。我们的结果表明 DNA 折纸可以作为控制疫苗中佐剂间距和共同递送抗原的平台。