Cytokine release upon in vitro stimulation of splenocytes and superficial cervical lymph node (LN) cells with hF.IX-containing or mock media. Average numbers ± SD are for 3 individual animals/experimental group of cells isolated from C3H/HeJ hemophilia B mice treated with hF.IX-derived peptide 2A-54 (▴) or saline control (□). Cells were isolated 4 months after hepatic AAV-hF.IX gene transfer. (A-C) Splenocytes. (D-F) LN cells. (A,D) IFN-γ. (B,E) IL-10. (C,F) TGF-β.