935 Designing polymers for the display of exogenous ligands to engage synthetic receptors on engineered T cells
Year: 2026
Type: conference-abstract
Abstract: Background Adoptive cellular immunotherapies have revolutionized the traditional cancer treatment paradigm, particularly with various hematologic malignancies. Their application in solid tumors, however, falls short due to an immunosuppressive tumor microenvironment and abnormal vasculature where cells lose persistence and functionality. Current clinical applications of adoptive immunotherapies rely on endogenous protein markers for targeting and activation of native effector function, making them susceptible to on-target off-tumor activity, systemic toxicity, and dysfunction. For these reasons, we investigate an exogenous small molecule capable of engaging various synthetic receptors on engineered T cells to drive transgene expression. To achieve activation, we synthesize biocompatible polymers with pendant small molecule ligands, varying the molecular weight (MW) and valency. Our approach seeks to revitalize adoptive immunotherapy in solid tumors through material interactions and careful transgene selection.Methods Polymers were synthesized with reversible addition-fragmentation chain transfer polymerization varying MW from 25 – 100 kDa. Reactions were carried out at 70°C for 6 to 12 hours followed by precipitation. MW and composition were characterized by gel permeation chromatography and proton nuclear magnetic resonance spectroscopy, respectively.Jurkat T cells were transduced by lentivirus produced in HEK239T cells following their transfection with Lipofectamine 3000 and sequence confirmed plasmids.In vitro T cell activation by polymer constructs was carried out for 48 hours, with doses normalized to ligand concentration, followed by flow cytometry or plate reader quantification. Multiple reporter transgene cassettes have been utilized, including a constitutive and inducible fluorescent or luminescent protein.Results Activation of engineered T cells was maximal for a 100kDa polymer with a ligand density of approximately 2%. Dose responses with this polymer showed EC50 values as low as 0.89 nM, on a ligand concentration basis, and as high as 50x activation above background. A 25kDa polymer with a density of 1% displayed a quarter of the activity of a 100kDa polymer also with 1% ligand. By increasing the ligand density of a 25kDa polymer to 3%, activation levels approached that of a 50kDa polymer with a density of 2%. However, both constructs remain below half of the fold induction seen for the 100kDa, 2% ligand polymer.Conclusions By assembling polymer constructs of varying MW, number of pendant ligands, and macromolecular structure we can efficiently drive synthetic receptor signal induction of engineered T cells in vitro. Our work aims to shift the landscape of engineered cellular immunotherapies from natural ligands and signaling pathways to a fully customizable cellular response based on designer materials.
Authors: John T Wilson, Jonathan Brunger, Jack Loken
Institution: Vanderbilt University
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,490
OpenAlex ID: W7225198350