Abrogation of Vγ9Vδ2 T-cell responses by CD277 expression knockdown. (A) Left: Surface expression of CD277 molecules on human HEK293FT clones after transduction with lentivirus delivering irrelevant (shControl) or CD277-specific (sh#240 and sh#284) shRNAs. Open histograms represent control IgG. The value for the intensity of specific CD277 staining (mAb 103.2) is indicated. Right: CD107a/b expression on human Vγ9Vδ2 T cells (line GUI) after coculture with shRNA-transduced HEK293FT clones, pretreated for 2 hours with either anti-CD277 mAb (20.1; 10 μg/mL) or NBP (pamidronate, 100μM). Numbers adjacent to outlined areas indicate the percentage and mean of fluorescence intensity (MFI) of CD107a/b⁺ T cells. (B) CD107a/b expression and IFN-γ production by Vγ9Vδ2 T cells (line GUI) after incubation with shRNA-transduced HEK293FT clones pretreated for 2 hours with either anti-CD277 mAb (left, 20.1; 10 μg/mL) or NBP (right, pamidronate, 100μM). Data are percentage of CD107a⁺ (black circles) or IFN-γ⁺ (white circles) T cells versus the value for the intensity (MFI) of specific CD277 staining (mAb 103.2). sh#284, n = 6; sh#240, n = 3; and shControl, n = 3. Regression lines and calculated r² values (0.95 and 0.75, for IFN-γ; 0.96 and 0.76 for CD107a/b) are indicated on the graphs.