Blocking the IFN I receptor eliminates capsid-specific CD8⁺T-cell responses. (A) Experimental timeline. WT mice received PBS or αIFNAR-1 antibody 1 day before IM injection of AAV2-SIINFEKL (n = 4/group). Capsid-specific CD8⁺ T-cell responses were assessed 7 days later. (B) Quantification of tetramer-positive cells from peripheral blood of control or treated mice. The dotted line at 0.1% represents the limit of detection of capsid-specific CD8⁺ T cells using the tetramer. (C) Experimental timeline of OT-1 adoptive-transfer experiments. WT mice received PBS or αIFNAR-1 antibody 1 day before IM injection of AAV2-SIINFEKL (n = 4/group). Mice were injected with 5 × 10⁶ CTV-labeled OT-1 cells 1 day later. (D) Representative plots of proliferation of adoptively transferred OT-1 cells. (E) Quantification of the percent proliferation, percent divided (percent of original cells that divided at least once), and the division index (the average number of cells that a dividing cell became). Data points are averages ± SEM. P values: (B) *P =.04; (E) **P =.004 for percent proliferation, *P =.014 for division index, **P =.007 for percent divided.