Kupffer cells phagocytose desialylated platelets. (A) SD-IVM of the liver of wild-type mice i.v. injected with desialylated platelets labeled with CellTracker Red dye. Representative images taken at the indicated time points. Kupffer cells were labeled using an anti-F4/80 antibody. Note how the CellTracker dye leaks from the platelet into the Kupffer cell body, thereby turning it red. Scale bars are 34 µm. (B) SD-IVM of the liver of wild-type mice i.v. injected with desialylated pHrodo-labeled platelets. Representative images taken at the indicated time points. Kupffer cells were labeled using an anti-F4/80 antibody. Scale bars are 34 µm. (C) Quantification of the pHrodo signal over time from four mice injected with pHrodo-labeled platelets. A.U., arbitrary unit. (D) 3D reconstruction of a Kupffer cell after injection of CellTracker Red–labeled platelets. Scale bar is 100 µm. (E) 3D reconstruction of a Kupffer cell after injection of pHrodo-labeled platelets. Scale bar is 100 µm. Results from all experiments shown are representative of at least three independent experiments.