PV-1/FELS antigen is not expressed on typical fenestrated endothelia in kidney glomeruli or in liver sinusoids. Liver was stained with 174/2 (A-B) or neg co, 3G6, (C) followed by FITC–anti–mouse IgG1 second-stage antibody. Kidney (D-F) was double stained with 174/2 followed by PE–anti–mouse IgG1 and FITC–anti-FVIII. The arrows point to portal tracts in panel A (higher magnification in B) and the arrow points to a glomerulus (GL) in panel D.