22Rv1 tumor exosomes downregulate cell-surface NKG2D expression on NK cells and CD8⁺ T cells.

<p>Purified 22Rv1 tumor exosomes or control fibroblast (WPMY1) exosomes were incubated for 24 h with healthy PMBCs, and flow cytometry was performed to determine the surface expression of NKG2D. (A) Representative dot-plots of flow cytometry gating scheme used to analyze NKG2D expression. (B) The bar graphs show the proportion of NKG2D-positive CD8⁺ T cells and NK cells relative to untreated cells (normalized to a value of 100). (C) The line graphs show the proportion of NKG2D-positive cells relative to untreated cells (normalized to a value of 100) when 22Rv1 exosomes were added at doses of 2–20 µg. (D) The percentage inhibition of NKG2D expression on CD8⁺ T cells and NK cells when 22Rv1 exosomes were treated with a mixture of anti-ULBP1-5 and MIC mAbs or anti-CD63 mAb. The graphs show mean ± SE (n = 8) from 2 independent experiments. * <i>P</i><0.05; ** <i>P</i><0.01.