Immunofluorescence staining of human F.IX in mouse liver. (A) Uninjected animal. (B through E) Mice intravenously injected with 2 × 10¹¹ particles of AAV-CMV-F.IX at day 1 of life. (B) Day 5 postinjection. (C and D) Day 240 postinjection. (E) Day 300 postinjection. Original magnification × 200 (×400 in E).