Mechanical regulation of T cell activation

Adoptive T cell immunotherapy is emerging as a powerful approach to treat diseases ranging from cancer to autoimmunity. T cell therapy involves isolation, modification, and reintroduction of T cells as “living drugs” to induce a durable response. A key capability to fully realize the potential of T cell therapies is effective manipulation of ex vivo T cell activation, with the aim of increasing T cell production and promoting specific phenotypes. While initial efforts to modulate T cell activation have heavily focused on mimicking biochemical signaling and ligand-receptor interactions between T cells and antigen presenting cells (APCs), there is increasing appreciation for understanding the role of mechanics at this interface and utilizing these insights to improve T cell activation systems. The aims of this dissertation is to contribute to this understanding by elucidating how mechanical properties of an activating surface regulate T cell activation, and apply these insights to generate biomaterial based systems to enhance activation from leukemia patient derived T cells. We first use a hydrogel system to investigate patterns T cell activation to substrate stiffness, discovering a biphasic response of T cell activation to stiffness that is synergist with ligand density. We then generate electrospun fiber scaffolds as an alternative platform to improve T cell expansion; we discover that 3D geometry in the form of fiber diameter and span lengths affects T cell activation. Lastly, we characterize the starting makeup of T cell populations from leukemia patients to study patterns of T cell exhaustion, utilizing the developed electrospun fiber scaffold system to enhance expansion of exhausted T cells from leukemia patients, and demonstrate patient-specific responses to different scaffold formulations. This approach allows for engineering of biomaterial designs that can leverage T cell mechanobiology to enhance T cell activation, with potential to be tailored to patient-specific expansion conditions and increasing the availability of T cell therapy to a wider range of patients.