Adoptive transfer of γδ T cells is a novel immunotherapeutic approach to glioblastoma. Few recent studies have shown the efficacy of γδ T cells against glioblastoma, but no previous studies have identified the ligand–receptor interactions between γδ T cells and glioblastoma cells. Here, we identify those ligand–receptor interactions and provide a basis for using γδ T cells to treat glioblastoma. Vγ9Vδ2 T cells were generated from peripheral blood mononuclear cells of healthy donors using artificial antigen presenting cells. MICA, ULBP, PVR and Nectin-2 expression in 10 patient-derived glioblastoma (PDG) cells were analyzed. The in vitro cytokine secretion from the γδ T cells and their cytotoxicity toward the PDG cells were also analyzed. The in vivo anti-tumor effects were evaluated using a U87 orthotopic xenograft glioblastoma model. Expression of ligands and cytotoxicity of the γδ T cells varied among the PDG cells. IFN-γ and Granzyme B secretion levels were significantly higher when γδ Tcells were co-cultured with high-susceptible PDG cells than when they were co-cultured with low-susceptible PDG cells. Cytotoxicity correlated significantly with the expression levels of DNAM-1 ligands of the PDG cells. Blocking DNAM-1 resulted in a decrease in γδ T cell–mediated cytotoxicity and cytokine secretion. Intratumoral injection of γδ T cells showed anti-tumor effects in an orthotopic mouse model. Allogenic γδ T cells showed potent anti-tumor effects on glioblastoma in a DNAM-1 axis dependent manner. Our findings will facilitate the development of clinical strategies using γδ T cells for glioblastoma treatment.

The association between obesity and the risk of glioma remains unclear. We sought to evaluate the potential association between general and abdominal obesity and the risk of glioma based on a nationwide population-based cohort study of Koreans. Using data from the Korean National Health Insurance System cohort, 6,833,744 people older than 20 years who underwent regular national health examination in both 2009 and 2011 were followed until the end of 2017. We documented 4771 glioma cases based on an ICD-10 code of C71 during the median follow-up period of 7.30 years. Individuals with a body mass index (BMI) ≥ 25.0 kg/m² were at significantly higher risk of developing glioma than those with a BMI < 25.0 kg/m² (HR 1.08 CI 1.02–1.15). Individuals with a waist circumference (WC) ≥ 90 cm (males)/85 cm (females) also had a significantly higher risk of glioma than those with a WC < 90 cm (males)/85 cm (females) (HR 1.16 CI 1.09–1.24). In the group with a BMI ≥ 25.0 kg/m², individuals with abdominal obesity were at significantly higher risk of developing glioma (HR 1.18 CI 1.09–1.27) than those without abdominal obesity. The role of abdominal obesity in this association was stronger in women than in men. To the best of our knowledge, this is the first demonstration that obese people may be at higher risk of glioma, especially centrally obese people from an Asian population with a BMI ≥ 25.0 kg/m². Loss of visceral fat in people with abdominal obesity may reduce their risk of developing glioma.

Although PD-1 blockade is effective for treating several types of cancer, the efficacy of this agent in glioblastoma is largely limited. To overcome non-responders and the immunosuppressive tumor microenvironment, combinational immunotherapeutic strategies with anti-PD-1 need to be considered. Here, we developed IL-12-secreting mesenchymal stem cells (MSC_IL-12) with glioblastoma tropism and evaluated the therapeutic effects of anti-PD-1, MSC_IL-12, and their combination against glioblastoma. Therapeutic responses were evaluated using an immunocompetent mouse orthotopic model. Tumor-infiltrating lymphocytes (TILs) were analyzed using immunofluorescent imaging. Single-cell transcriptome was obtained from mouse brains after treatments. Anti-PD-1 and MSC_IL-12 showed complete tumor remission in 25.0% (4/16) and 23.1% (3/13) of glioblastoma-implanted mice, respectively, and their combination yielded synergistic antitumor efficacy indicated by 50.0% (6/12) of complete tumor remission. Analyses of TILs revealed that anti-PD-1 increased CD8⁺ T cells, while MSC_IL-12 led to infiltration of CD4⁺ T cells and NK cells. Both therapies reduced frequencies of Tregs. All these aspects observed in each monotherapy group were superimposed in the combination group. Notably, no tumor growth was observed upon rechallenge in cured mice, indicating long-term immunity against glioblastoma provoked by the therapies. Single-cell RNA-seq data confirmed these results and revealed that the combined treatment led to immune-favorable tumor microenvironment-CD4⁺, CD8⁺ T cells, effector memory T cells, and activated microglia were increased, whereas exhausted T cells, Tregs, and M2 polarized microglia were reduced. Anti-PD-1 and MSC_IL-12 monotherapies show long-term therapeutic responses, and their combination further enhances antitumor efficacy against glioblastoma via inducing immune-favorable tumor microenvironment.

Background: Certain cancers present challenges for treatment because they are resistant to immune checkpoint blockade (ICB), attributed to low tumor mutational burden and the absence of T cell-inflamed features. Among these, glioblastoma (GBM) is notoriously resistant to ICB. To overcome this resistance, the identification of T cells with heightened stemness marked by T-cell factor 1 (TCF1) expression has gained attention. Several studies have explored ways to preserve stem-like T cells and prevent terminal exhaustion. In this study, we investigate a target that triggers stem-like properties in CD8 T cells to enhance the response to ICB in a murine GBM model. Methods: Using Fcgr2b^−/− mice and a murine GL261 GBM model, we confirmed the efficacy of anti-programmed cell death protein-1 (PD-1) immunotherapy, observing improved survival. Analysis of immune cells using fluorescence-activated cell sorting and single-cell RNA sequencing delineated distinct subsets of tumor-infiltrating CD8 T cells in Fcgr2b^−/− mice. The crucial role of the stem-like feature in the response to anti-PD-1 treatment for reinvigorating CD8 T cells was analyzed. Adoptive transfer of OT-I cells into OVA-expressing GL261 models and CD8 T cell depletion in Fcgr2b^−/− mice confirmed the significance of Fcgr2b^−/− CD8 T cells in enhancing the antitumor response. Last, S1P₁ inhibitor treatment confirmed that the main source of tumor antigen-specific Fcgr2b^−/− CD8 T cells is the tumor-draining lymph nodes (TdLNs). Results: In a murine GBM model, anti-PD-1 monotherapy and single-Fc fragment of IgG receptor IIb (FcγRIIB) deletion exhibit limited efficacy. However, their combination substantially improves survival by enhancing cytotoxicity and proliferative capacity in tumor-infiltrating Fcgr2b^−/− CD8 T cells. The improved response to anti-PD-1 treatment is associated with the tumor-specific memory T cells (Ttsms) exhibiting high stemness characteristics within the tumor microenvironment (TME). Ttsms in the TdLN thrives in a protective environment, maintaining stem-like characteristics and serving as a secure source for tumor infiltration. This underscores the significance of FcγRIIB ablation in triggering Ttsms and enhancing ICB therapy against GBM. Conclusions: Deletion of FcγRIIB on CD8 T cells leads to the generation of a Ttsms, which is localized in TdLN and protected from the immunosuppressive TME. Incorporating these highly stemness-equipped Ttsms enhances the response to anti-PD-1 therapy in immune-suppressed brain tumors.