DNA Origami Scaffold-Based Peptide-Major Histocompatibility Complex Multimers for Spatial Imaging of T Cells

Visualizing the spatial distribution of antigen-specific T cells is essential for understanding immune responses and improving therapeutic strategies. However, detecting low-affinity antigen-specific T cells and enhancing signals from low-abundance populations remain challenging due to limitations in sensitivity. Here, we report DNA origami scaffold-based peptide-major histocompatibility complex multimers (DOS-pMHCs) with precise spatial organization of pMHC and signaling molecules on the nanoscale for enhanced in situ visualization of antigen-specific T cells. The two-dimensional triangular DNA origami precisely organizes pMHCs and signaling molecules with high valency, significantly improving binding to antigen-specific T cells and signal amplification. These DOS-pMHCs facilitate enhanced visualization of antigen-specific T cells in lymphoid tissues compared to traditional tetramers. Moreover, we show that DOS-pMHCs enable the in situ detection of autoimmune T cells with lower affinity T cell receptors (TCRs), which are difficult to identify using traditional tetramers. This in situ detection strategy provides a powerful tool for mapping the spatial distribution of antigen-specific T cells, thus holding great potential for advancing our understanding of immune responses and guiding personalized immunotherapy.