Ex vivo enhancement of CD8+ T cell activity using functionalized hydrogel encapsulating tonsil-derived lymphatic endothelial cells.

Rationale: This study investigates a method for programming immune cells using a biomaterial-based system, providing an alternative to traditional ex vivo cell manipulation techniques. It addresses the limitations of engineered adoptive T cell therapies, such as T cell exhaustion, by introducing a gelatin-hyaluronic acid (GH-GMA) hydrogel system. Methods: We characterized tonsil mesenchymal stem cells (TMSCs), lymphatic endothelial cells (T-LECs), stimulated T-CD8+ T cells (STCs), and GH-GMA biomaterials. The 10% 5:1 GH-GMA hydrogel, loaded with anti-CD28, cytokines interleukin-2 (IL-2) and vascular endothelial growth factor C (VEGF-C), forms a functional hydrogel capable of releasing these immune-stimulating factors. T-LEC spheroids, derived from tonsil mesenchymal stem cells (TMSCs), were encapsulated within the hydrogel to act as antigen-presenting cells for T cells. Results: Co-encapsulation of STCs and T-LEC spheroids in the functional hydrogel resulted in significant expansion and enrichment of STCs during cultivation. Moreover, when cancer cells were co-encapsulated with STCs and T-LECs, there was increased migration of STCs towards the cancer cells and elevated expression of PD-L1 on the cancer cells. Conclusions: These findings suggest that the GH-GMA hydrogel, combined with anti-CD28, IL-2, VEGF-C, and T-LEC spheroids, enhances T cell activity, presenting a promising platform for cancer immunotherapies and modulation of the suppressive tumor microenvironment.