Quantification of relative FoxP3 mRNA levels in CD4⁺ or CD4⁻ T cells derived from naive control or AAV-ApoE/hAAT-hFIX gene-transferred C57BL/6 mice 60 days before the experiment. Some of control or gene-transduced animals were challenged by subcutaneous administration of 5 μg hFIX formulated in CFA 5 days prior to PCR analysis. cDNA samples were subjected to real-time quantitative PCR analyses using primers and an internal fluorescent probe specific for FoxP3 or HPRT. The relative quantity of FoxP3 in each sample was normalized to the relative quantity of HPRT. FoxP3 transcript levels in naive CD4⁺ cells are reported as 100%. Results were shown as average ± SD (n = 3 per group). *P < .05 compared with other experimental groups.