Fig. 4.

Trogocytosis of Rae-1 is coupled with clathrin-dependent NKG2D down-modulation. (A) WT, DAP10^−/−/DAP12^−/−, or Prf^−/− NK cells were cocultured with RMA/Rae-1δ for 1 h, and then Rae-1 acquisition by NK cells was analyzed as described in Fig. 3E. (B and C) WT NK cells were treated with the indicated blocking mAbs (B) or indicated inhibitors (C) for 30 min, and then cocultured with RMA/Rae-1δ as described in A. Percent trogocytosis was calculated as (MFI of anti–Rae-1 mAb staining in the presence of inhibitor)/(MFI of anti–Rae-1 mAb staining in the absence of inhibitor). Data represent means plus SDs of triplicates. *P < 0.05, **P < 0.01, compared with the absence of the inhibitor. (D and E) NK cells were cocultured with RMA/Rae-1δ in the presence or absence of the indicated inhibitors or in the medium containing 0.45 M sucrose for the indicated periods of time. Then cell surface expression of NKG2D and Rae-1 on NK cells was analyzed. Delta MFI was calculated by subtracting MFI of isotype control mAb staining from MFI of specific mAb staining. Similar results were obtained in three independent experiments.