Douglas Travis R, Alexander Shana, Chou Leo Y T
Institute of Biomedical Engineering, University of Toronto, Toronto M5S 2E3, Canada.
ACS Nano. 2025 Jan 14;19(1):621-637. doi: 10.1021/acsnano.4c11183. Epub 2025 Jan 6.
Immune complexes (ICs), formed via antibody (Ab)-antigen (Ag) binding, trigger diverse immune responses, which are critical for natural immunity and have uses for vaccines and immunotherapies. While IC-elicited immune responses depend on its structure, existing methods for IC synthesis produce heterogeneous assemblies, which limits control over their cellular interactions and pharmacokinetics. In this study, we demonstrate the use of DNA origami to create synthetic ICs with defined shape, size, and solubility by displaying Ags in prescribed spatial patterns. We find that Ag arrangement relative to the spatial tolerance of IgG Fab arms (∼13-18 nm) determines IC formation into "monomeric" versus "multimeric" regimes. When Ag spacing matches Fab arm tolerance, ICs are exclusively monomeric, while spacing mismatches favor the formation of multimeric ICs. Within each IC regime, parameters such as the number of Ags and Ab-Ag ratios, as well as DNA origami shape, further fine-tune IC size, shape, and Fc valency. These parameters influenced IC interactions with FcγR-expressing immune cells, with uptake by macrophages showing greater sensitivity to IC cross-linking while dendritic cells were more responsive to Ab valency. Our findings thus provide design principles for controlling the structure and cellular interactions of synthetic ICs and highlight DNA origami-scaffolded ICs as a programmable platform for investigating IC immunology and developing FcγR-targeted therapeutics and vaccines.
免疫复合物（ICs）通过抗体（Ab）-抗原（Ag）结合形成，可触发多种免疫反应，这些反应对天然免疫至关重要，并在疫苗和免疫疗法中具有应用价值。虽然IC引发的免疫反应取决于其结构，但现有的IC合成方法会产生异质组装体，这限制了对其细胞相互作用和药代动力学的控制。在本研究中，我们展示了利用DNA折纸技术，通过以规定的空间模式展示抗原，来创建具有确定形状、大小和溶解性的合成ICs。我们发现，相对于IgG Fab臂的空间耐受性（约13 - 18纳米），抗原的排列决定了IC形成进入“单体”与“多聚体”状态。当抗原间距与Fab臂耐受性匹配时，ICs完全是单体形式，而间距不匹配则有利于多聚体ICs的形成。在每种IC状态下，诸如抗原数量、Ab-Ag比率以及DNA折纸形状等参数，可进一步微调IC的大小、形状和Fc价态。这些参数影响了IC与表达FcγR的免疫细胞的相互作用，巨噬细胞的摄取对IC交联表现出更高的敏感性，而树突状细胞对抗体价态更敏感。因此，我们的研究结果为控制合成ICs的结构和细胞相互作用提供了设计原则，并突出了DNA折纸支架ICs作为一个可编程平台，用于研究IC免疫学以及开发靶向FcγR的治疗方法和疫苗。
