Veto activity of ex vivo–expanded CD34+cells: detection of veto effect at a veto-to-responder cell ratio of 0.125.
Limiting dilution of CTL-p in cultures of responder cells stimulated against cells from the donor of the CD34+ cells in the presence (●) or absence (○) of ex vivo–expanded cells was carried out, and the CTL-p frequency was calculated. The parameters for the different regression lines were as follows. In the absence of CD34+-expanded cells (○), ln y = − 2.6 × 10−5 x + ln 106.1 (R2 = 0.999, SE = 3.1 × 10−7,P = .007, f with 95% CI = 2.2 × 10−5 to 3 × 10−5). In the presence of CD34+-expanded cells (●), ln y = − 0.18 × 10−5 x + ln 101.1 (R2 = 0.964, SE = 3.5 × 10−7,P = .121, f with 95% CI = −2.6 × 10−6to 6.3 × 10−6). In the presence of ex vivo–expanded cells (●), f was significantly lower (P < .001) than in the absence of these cells (○).
