Time course of β-galactosidase activity during T lymphopoiesis. (A) CD34⁺CD2⁻ cells were transduced at MOIs of 10, 5, and 1 or were mock-transduced with an equivolume of medium (control). Two samples were taken at each time point and independently incubated with X-gal at 150 μg/mL, and the number of cells staining positively was enumerated. Data are mean values ± SEM of triplicate readings in a representative experiment. Data from seven independent experiments were analyzed after 14 days or 35 days to compare expression of β-galactosidase after infection with rAAV at (B) MOI = 10 or (C) MOI = 1. Mean values are denoted by a straight line and P values were calculated using a two-tailed unpaired t-test.