BTN3A1 and neoplasm: The non-reactivity of Vγ9Vδ2 T cells with the conditioned medium of BrHPP pre-treated tumor cells or in co-culture with these cells separated by a porous membrane (Transwell), demonstrated that BrHPP was able to penetrate inside the tumor cell and to activate membrane BTN3A1 shown to be essential for this activation (19).