Precise control of immune modulation using DNA scaffold-mediated biomaterial functionalization

Abstract

Abstract Synthetic materials displaying multi-modal ligands with exact chemiophysical properties for immune modulation are valuable research tools and a promising therapeutic platform. However, precise chemical conjugation of multiple proteins on biomaterial surfaces is challenging. Through DNA hybridization-mediated biomolecule loading, we achieved high density and precise ratiometric control of multiple ligands on nano-/micro-particles. We found increasing ratios of anti-CD3 to anti-CD28, 1:5, 1:3, 1:1, 3:1 to 5:1, on microparticles yielded a linear increase of ex vivo expansion of primary human CD4+ and CD8+ T cells until reaching a plateau at 3:1 ratio. For CD8+ T cells, the ratio of 3:1 resulted in the highest percentage of central memory cells, 51.4 ± 7.2% vs. 14.4 ± 7.6% for 1:5 ratio (n = 5 donors). Particle surface presentation of IL-2 using an anti-IL-2 antibody (in trans to CD3/28 particles) yielded ~3 fold more ex vivo expansion of CD4+ and CD8+ T cells in 14 days when compared to the equivalent dose of soluble IL-2. Using intratumoral injection of microparticles presenting a ligand for a synthetic Notch receptor, we locally induced chimeric antigen receptor (CAR) expression on systemically infused engineered T cells and observed CAR T cell killing of the injected tumors, while sparing the uninjected identical tumors in the contralateral flank. These results highlight the potential of this platform in achieving better control of therapeutic cell manufacture and local tuning of immunotherapies. Ongoing work is using DNA origami-mediated patterning to dissect spatial requirements of various T cell activating ligands to better understand critical parameters of T cell activation with the goal to improve the design of immunotherapies.