Immunohistochemical localization of VWF expression in liver sections from VWF^–/– mice after intravenous administration of murine VWF cDNA. Data are presented pairwise. Sections on the left were stained with a specific anti-VWF antibody, and sections on the right (controls) were treated with an irrelevant antibody (rabbit IgG). (A) Naive wild-type C57BL/6 mouse stained with rabbit anti–human VWF antibody. Dense endothelial staining of VWF is observed. (B) Same as upper left but stained with rabbit IgG (control). (C) Liver, VWF^–/–, 48 hours after administration of 250 μg eGFP cDNA plasmid (negative control), anti–human VWF antibody. (D) Same as middle left, control antibody. No staining is observed in either sample. (E) Liver, VWF^–/– mouse, 48 hours after administration of 250 μg VWF cDNA plasmid, anti–human VWF antibody. (F) Same as lower left, control antibody; strong diffuse staining is observed within the liver parenchyma. Bar represents 500 μm.