Targeting BTN2A1 enhances Vγ9Vδ2 T cell effector functions and triggers tumor cells pyroptosis

Vγ9Vδ2 T cells are potent but elusive cytotoxic effectors. Means to stimulate their function could lead to powerful new cancer immunotherapies. BTN2A1, a surface protein has recently been shown to bind the Vγ9 chain of the γδ TCR but its precise role in modulating Vγ9Vδ2 T cells functions remains unknown. Here we show that 107G3B5, a monoclonal anti-BTN2A1 agonist antibody, significantly enhances Vγ9Vδ2 T cell functions against hematological or solid cell lines and against primary cells from adult acute lymphoblastic leukemia patients. New computer vision strategies applied to holotomographic microscopy videos show that 107G3B5 enhances the interaction between Vγ9Vδ2 T cells and target cells in a quantitative and qualitative manner. In addition, we provide evidence that Vγ9Vδ2 T cells activated by 107G3B5 induce caspase 3/7 activation in tumor cells, thereby triggering their death by pyroptosis. We thus demonstrate that targeting BTN2A1 with 107G3B5 enhances the Vγ9Vδ2 T cell antitumor response by triggering the pyroptosis-induced immunogenic cell death.