Figure 2.

Optimization of a protocol that prevents inhibitor formation by administration of hF.IX protein and rapamycin. (A) Experimental timeline of the optimal protocol. For immune modulation, C3H/HeJ F9^−/− mice received hF.IX IV injections (0.1 IU/dose) twice per week for 4 weeks. During that time, rapamycin was administered orally once per day. One week before the end of this 1-month regimen, AAV1-CMV-hF.IX (1 × 10¹¹ vg/mouse) was given IM. Left panels: Comparison of IgG1 (B) and inhibitor (F) formation against hF.IX, of systemic hF.IX expression (D), and of coagulation times [aPTT (H)] at 1 month after vector administration in mice that had received vector only; or 2 IV doses of hF.IX (0.1 IU) plus 3 oral doses of rapamycin per week (with the first and last 30 min prior to hF.IX administration); or the optimal protocol (2 IV doses of F.IX plus daily rapamycin). Right panels: IgG1 (C) and inhibitor (G) formation against hF.IX, systemic hF.IX expression (E), and coagulation times [aPTT (I)] as a function of time after vector administration in mice that had received the optimal protocol (2 IV doses of F.IX plus daily rapamycin).