Modulation of immune responses induced by FVIII plasmid injection after adoptive transfer of CD4⁺Foxp3⁺ T cells from FVIII plasmid-treated HemA/Foxp3-Tg mice into naive HemA mice. CD4⁺ T cells were isolated from the spleens of HemA/Foxp3-Tg mice 2 weeks after FVIII plasmid treatment (n = 9), and from untreated HemA/Foxp3-Tg mice (n = 3), and adoptively transferred into naive HemA mice. Recipient mice as well as a control group of naive HemA mice (n = 6) were subsequently challenged with FVIII plasmid injection 1 day after adoptive transfer. (A) Flow chart showing overview of these adoptive transfer experiments. (B) FVIII activities and anti-FVIII antibody titers were measured (as described in Figure 2) 3 weeks after adoptive transfer and FVIII plasmid injection.