Hemostatic measurements after administration of the HD adenoviral vector AdFTC/cFIX/ChMAR and generation of antiadenoviral-neutralizing antibodies in canine serum after intravenous injection. The first dog (hemophilia B dog G11, 5.8 kg) received 8.57 × 10¹¹ vp/kg body weight and the second dog (hemophilia B dog G21, 11.7 kg) received 6.0 × 10¹¹ vp/kg body weight of the HD vector AdFTC/cFIX/ChMAR. Blood samples were collected periodically. Each line represents an individual animal. ○ indicates hemophilia B dog G11; •, hemophilia B dog G21. (A) WBCT and (B) cFIX expression levels in hemophilia B dogs after administration of the recombinant adenoviral vector AdFTC/cFIX/ChMAR. Periodic blood samples were obtained and analyzed by cFIX ELISA. Plasma concentrations in normal dogs were considered to contain 5 to 11.5 μg/mL. Canine serum was analyzed for the presence of antiadenoviral-neutralizing antibodies in dog G11 (C) and dog G21 (D). The principle of this test is to analyze at which dilution the canine serum is able to inhibit the transduction of a reporter virus into HeLa cells. The neutralizing-antibody titer was defined as the reciprocal of the highest dilution of serum at which the infectivity of a reporter virus was decreased by at least 50%.