A Microgel-Based Platform for Tunable Expansion and Function of γδ T-cells

Current {gamma}{delta} T-cell expansion protocols often sacrifice functionality for yield and largely ignore the context of activation. Here we utilize a tunable alginate microgel system functionalized with anti-CD3 and co-stimulatory antibodies (CD28 or CD2) to investigate the impact of biochemical signaling and substrate mechanics on {gamma}{delta} T-cell activation. Microgel-mediated expansion was compared to conventional soluble antibodies and TransAct beads. The microgels enhanced {gamma}{delta} T-cell expansion compared to soluble antibodies, allowed for controlled tuning of differentiation state, and promoted higher NKG2D, IFN-{gamma} and TNF- expression levels. Functionally, microgel-expanded {gamma}{delta} T-cells exhibited superior cytotoxicity against both solid and liquid tumor targets. This system also allowed elucidation of the differences in stimulation requirements for various donors, based on the starting phenotype. These findings establish a tunable platform for engineering {gamma}{delta} T-cells with improved therapeutic potential. Significance Statement{gamma}{delta} T-cells have shown promising therapeutic effects when used for T cell-based immunotherapy to treat solid tumor. However, achieving rapid expansion of {gamma}{delta} T-cells while maintaining their functionality remains a major challenge, especially given the heterogeneous responses from donors. We demonstrate that a tunable microgel system with flexible presentation of stimulatory cues improves {gamma}{delta} T-cell expansion while preserving cytotoxic function and reveal how starting phenotypes influence responses to activation. These understandings will provide design rationale to enable patient-specific treatment for optimal therapeutic outcomes.