Quantification of hF.IX⁺ hepatocytes 1 month after adoptive transfer of cap-CD8 or con-CD8 cells. Mice had been transduced with AAV2-hF.IX (A) or AAV2(Y-F)-hF.IX (B) vector. Percent decrease of hF.IX levels from cap-CD8 cells is indicated. Data from individual mice (n = 3-4 per group, with 10 random low-power fields for each liver) as well as averages are graphed. P values for significant differences are indicated. Representative hF.IX stains (red) are shown for AAV2 (C) and AAV2(Y-F) (D).