Pathogen-like Nanoassemblies of Covalently Linked TLR Agonists Enhance CD8 and NK Cell-Mediated Antitumor Immunity.

Therapies based on Toll Like Receptor agonists (TLRa) are emerging as a promising modality for cancer immunotherapy to recruit antitumor T-cells in unresponsive immunologically "cold" tumors. Often, combinations of agonists are employed to synergistically enhance efficacy. However, low efficacy and severe toxicities deter these TLR-based therapeutics from further clinical applications. Studies have suggested that the rapid systemic diffusion of agonists to nontarget tissues is the primary cause. To address this challenge, we developed supramolecular nanotherapeutics of covalently linked TLRas for multivalent, synergistic interactions by drawing inspiration from immune recognition of pathogens. This new nanotherapeutic increased stimulation of key pro-inflammatory cytokines and remarkably enhanced CD8 and NK cell-mediated antitumor response while exhibiting ultralow off-target toxicity in an aggressive B16.F10 tumor model. Results from our studies thereby indicate that such supramolecular immune-agonist therapeutics may be further developed as a viable treatment modality for cancer immunotherapy.