In Vivo Activation of T-Cell Proliferation by Regulating Cell Surface Receptor Clustering Using a pH-Driven Interlocked DNA Nano-Spring.

Activation of T-cell proliferation specifically in a tumor is crucial for reducing the autoimmune side effects of antitumor immunotherapy. Herein, we developed a pH-driven interlocked DNA nano-spring (iDNS) to stimulate T-cell activation in vivo in response to the low pH value in a tumor microenvironment. The interlocked structure of iDNS provide a more rigid scaffold in comparison to double-stranded DNA for ligand assembly, which can help to control the spatial distribution of ligands with more accuracy. We have demonstrated that the pH-driven reversible reconfiguration of iDNS provides a powerful way to regulate the nanoscale distribution of T-cell receptors (CD3) on the cell surface. The relatively low pH value (pH 6.5) in a solid tumor was able to drive the springlike shrinking of iDNS and induce significant T-cell proliferation, leading to an enhanced antitumor effect, thus providing a tool for specifically inducing an immune response in a tumor for immunotherapy.