Expression of BST-2 in normal mouse organs and lymphoma xenografts. (A) Three-color confocal images of BST-2 staining (clone 129c, green), CD31 staining (red), and 4,6-diamidino-2-phenylindole counterstaining (blue) are shown. Although being undetectable in the vasculature of brain, heart, lung, liver, spleen, lymph nodes, kidney, intestine, and skeletal muscle, BST-2 was readily detectable in different lymphoma xenografts (Ramos, DoHH-2, SUDHL-4) in the same experiment, colocalizing to CD31 (yellow). As expected, a scattered cellular, but not vascular, expression of BST-2 was observed in lymphoid tissues. (B) Graphs displaying the spatial distribution of BST-2 and CD31 fluorescent signals in confocal microscopy were virtually superimposable. Scale bars represent 50 μm. Slides were viewed with an LSM510 Meta confocal microscope (Carl Zeiss) using 10×/0.45 W and 40×/1.2 W water objectives and Fluorescent Mounting Medium (Dako). Images were acquired with the LSM510 Meta confocal laser scanning microscope and software provided by the manufacturer (Carl Zeiss). Images were manipulated using ImageJ software, Version 1.42q (available at http://rsb.info.nih.gov/ij/).