Synthetic Viscoelastic Activating Cells for T Cell Engineering and Cancer Therapy

Immunotherapy shows promise in cancer treatment, but its effectiveness and durability remain limited, and improved technology for engineering immune cells is necessary. Here we develop a scalable platform that creates synthetic viscoelastic activating cells (SynVACs) with programmable mechanical and chemical properties. We demonstrate that the viscoelastic nature of SynVACs significantly impacts T cell functionality. Compared to rigid or elastic microspheres, SynVACs greatly enhance human T cell expansion, achieving approximately 90% chimeric antigen receptor (CAR) transduction efficiency. Additionally, SynVACs promote CD8+ T cell generation while suppressing regulatory T cell formation, resulting in enhanced tumor killing capability. Notably, expanding CAR-T cells with SynVACs leads to a ten-fold increase in T memory stem cells (TMSCs). These engineered CAR-T cells exhibit superior efficacy in eliminating tumor cells in a human lymphoma and ovarian xenograft mouse model, persisting in vivo for longer time period. These findings underscore the crucial role of mechanical signals in T cell engineering and highlight SynVACs' potential in CAR-T therapy and imunoengineering applications. CAR-T cells activated by SynVACs and Dynabeads were cultured and harvested at day 14, followed by sorting with a FACSAria II flow cytometer. The sorted cells were immediately dispatched to the UCLA Technology Center for Genomics and Bioinformatics (TCGB) Core for single cell TCR sequencing. The sequencing was executed with a 10X Genomics Chromium™ Controller Single Cell Sequencing System, as per the manufacturer's guidelines and the TCGB Core's standard protocol. Library preparation was accomplished using the Illumina TruSeq RNA Sample Prep Kit (Cat#FC-122-1001), and the sequencing was performed with 150 bp paired-end reads (5,000 reads/cell) on an Illumina NovaSeq system. Lastly, the reads were mapped to the human T cell receptor reference genome (hg38) using Cell Ranger VDJ. This allowed for the visualization of the frequencies of alpha or beta chain recombination events in CAR-T cells activated by SynVACs and Dynabeads.