EFFECT OF PATIENT DERIVED ΓΔ T CELLS AGAINST BTN2A1 EXPRESSING GBM CELLS

Background: Glioblastoma (GBM) is the most common, aggressive and malignant brain tumor. The current treatment strategies involve surgery followed by radiotherapy and temozolomide chemotherapy. Although immunotherapy has been successful in treating other cancers, GBM’s immunosuppressive tumor microenvironment and MHC class I downregulation limit the efficacy of the conventional αβ T cells. Therefore, ϒδ-T cells which can act without MHC have a greater ability to target GBM cells. Our study shows that BTN2A1, ligand required for ϒδ-T cells activation is expressed in GBM tumor tissues and U87 cell line and γδ T cells displayed better cytotoxic effect against BTN2A1-expressing GBM cell line.
Methods: PBMCs were isolated from GBM patient peripheral blood (5ml, n=5), from which γδ T cells and non-γδ T cells were sorted by MACS method. Sorted populations were co-cultured separately with U87 cells in 5:1 ratio (5 effector cells: 1 target cell) for 24 hours. After co-culture, T cells were removed and U87 viability assessed by MTT assay (reduced viability = cytotoxicity). BTN2A1 expression was quantified by Western blot in GBM tumor tissues (n=3) and U87 cells.
Results: Western blot confirmed BTN2A1 expression in GBM tissues and U87 cells. γδ T cells induced significantly greater U87 cytotoxicity versus non-γδ T cells at 24 h (MTT: ~45% vs ~72% viability, p<0.05), confirming superior cytotoxicity.
Conclusion: Patient-derived γδ T cells displayed superior cytotoxicity against BTN2A1-expressing GBM cells compared to non-γδ T cells.