Fig. 4.

Down-regulation of NKG2D on NK cells requires cell–cell contact and is independent of TGF-β. a TCD PBMC (upper compartment) were separated from sarcoma cells (lower compartment) by a porous membrane (0.4 μm) in trans-well experiments. Surface expression of NKG2D on NK cells was investigated after the unseparated coculture and the trans-well coculture, both in the presence of IL15 and incubated for 40 h. Data are combined from multiple experiments. b (i) NKG2D expression on NK cells was investigated after incubating TCD PBMC with IL15 in the presence or absence of recombinant TGF-β and TGF-β inhibitors (TGF-β-neutralizing antibody, SB-431542 and recombinant LAP). Data are combined from two experiments. (ii) NKG2D expression on NK cells in TCD PBMC was analyzed after the IL15-stimulated coculture with sarcoma cells in the presence or absence of TGF-β inhibitors. Data are combined from two experiments. c Surface expression of NKG2D on NK cells was measured after coculture of purified NK cells with sarcoma cells in the presence of IL15. Data are combined from multiple experiments. In all panels, IL15-stimulated samples are indicated by gray bars, white bars depict control incubations in medium only. Expression of NKG2D after IL15 stimulation was set to 1.00