Ex Vivo Expansion and Hydrogel-Mediated In Vivo Delivery of Tissue Resident Memory T Cells for Immunotherapy

Tissue-resident memory (TRM) T cells preferentially reside in peripheral tissues, serving as key players in tumor immunity and immunotherapy. Currently, the lack of effective approaches for expanding TRM cells and delivering these cells in vivo hinder the exploration of TRM cell-mediated cancer immunotherapy. Here, we report a nanoparticle artificial antigen-presenting cell (nano-aAPC) ex vivo expansion approach and an in vivo delivery system for TRM cells. Using the nano-aAPC platform, we expanded functional antigen-specific murine and human TRM-like CD8+ T cells ex vivo. We also developed an injectable macroporous hyaluronic acid (HA) hydrogel for delivery of TRM-like cells. TRM-like cells delivered in the optimized HA hydrogel trigger robust local and systemic antitumor immunity and show synergistic effect with anti-PD1 treatment. Our findings suggest that nano-aAPC-induced TRM-like cells, coupled with a hydrogel delivery system, offer an efficient way to advance the understanding of TRM cells-mediated cancer therapy. CD8+ T cells were isolated from OT-I transgenic mouse lymph nodes and spleens using CD8+ T cells isolation kits and magnetic columns (Miltenyi Biotech, CA, USA) according to the manufacturer’s protocol. On Day 0, isolated CD8+ T cells were incubated with nano-aAPCs in the B media containing different cytokines mixes. On Day 6 of culture, OT-I T cells expanded in the media containing nano-aAPCs in the presence of mIL-2 (TEff) or mIL-2, mIL-15, and mTGF-β (TRM-like) were harvested for RNA extraction with quick-RNA miniprep kit (Zymo research, CA, USA). Then RNA samples were submitted to Psomagen to generate RNA-seq libraries using TruSeq Stranded Total RNA Library Prep Kit (Illumina, CA, USA). Libraries were sequenced by a Illumina NovaSeq X Plus platform.