Anti-hF.IX titers for C3H/HeJ hemophilia B mice treated with hF.IX-derived peptide 2A-54 (▴) or saline control (•) 2 weeks after hepatic AAV-hF.IX gene transfer. Shown are IgG1 (A), IgG2a (B), and IgG2b (C) titers. Each data point represents an individual animal. Horizontal bars show average antibody titers. Numbers of mice are indicated for each cohort.