Fig. 6

TNFSF15 is an immunostimulatory factor that enhances CAR T cell cytotoxicity. A Cell surface staining of CD69 and CD25 in CAR T cells stimulated by plate-bound recombinant B7-H3-Fc protein with or without recombinant trimeric TNFSF15 protein. (n = 3 for 0, 100 ng/mL and = 2 for 400 ng/mL). Error bars denote SEM. B Tumor killing of U87 MG cells by B7-H3-targeting CAR T cells or control T cells at an E: T ratio of 1:2 after two-day co-culture with or without exogenous addition of recombinant TNFSF15 protein (n = 4). Error bars denote SEM. C Gene expression correlation between TNFSF15 and the T cell activation signature (GZMB、GZMK、GZMA、IFNG、TNF、IL2、IL2R、CD69 and CD137) in human GBM samples. Data were obtained from TCGA. D Schematic of a recent study that performed single-cell RNA sequencing on mouse skin-draining lymph nodes for probing cellular response to various cytokines, including TNFSF15 (TL1A). E Violin plots showing the expression levels of genes involved in T cell activation and NF-κB pathway in CD8⁺ T cells following PBS or TNFSF15 treatment in vivo. F-I Gene expression correlation between TNFSF15 and NFKB2 (F), NFKB1 (G), RELB (H) and ICAM1 (I) in human GBM samples. Data were obtained from TCGA. J Schematic of our proposed model. Inhibiting ARPC4 or NDUFV1 in GBM cells upregulates TNFSF15. TNFSF15 acts as an immunostimulatory factor that activates the NF-κB pathway in CAR T cells, leading to increased production and release of proinflammatory and cytotoxic factors, thus enhancing the anti-tumor activity of CAR T cells