Fig. 6

Natural killer group 2 member D (NKG2D) plays a role in mucosal associated invariant T (MAIT) cell activation by breast carcinoma cells. a Left plot: Flow cytometric analysis showing NKG2D receptor expression by primary MAIT cells in a breast duct tissue sample. Right graph: Aggregated results from five different breast tissue samples showing the percentage of MAIT cells or non-MAIT cells staining positively for NKG2D. b Flow cytometric analysis of the expression of known NKG2D ligands (major histocompatibility complex class I-related chain A and B [MICA/B], UL16-binding proteins 1–6 [ULBP1–6]) by primary nontransformed breast duct epithelial cells (top row, luminal subset; middle row, basal subset) compared with MDA-MB-231 breast carcinoma cells (bottom row). Staining with specific antibodies is shown as an open histogram with a heavy black line with geometric mean fluorescence intensity (gMFI) indicated in bold; gray filled histograms show isotype-matched negative control antibody staining with gMFI indicated in italic font. c Left plots: Tumor necrosis factor (TNF)-α expression by primary MAIT cells in CD161-selected peripheral blood mononuclear cell samples in response to Escherichia coli-pulsed MDA-MB-231 breast carcinoma cells in the presence or absence of an anti-NKG2D blocking antibody. Right graph: Quantification of anti-NKG2D blocking effect. The percentage of MAIT cells showing positive cytokine expression in the NKG2D blockade condition was normalized by the percentage positive in the unblocked condition. Symbols represent the results of independent experiments. P values are derived from two-tailed, one-sample t tests. APCs Antigen-presenting cells, n.s. Not significant, 5RU 5-(2-oxoprophylideneamino)-6-d-ribitylaminouracil