In vitro innate immune sensing of AAV vectors. (A) Strength of TLR9 signaling as determined by levels of IL-8 secretion by HEK-293-null and -293-TLR9 cells 6 hours after infection with ssAAV2-GFP or scAAV2-GFP or ssAAV-TM-hF.IX or scAAV-TM-hF.IX. (B) Activation of the inflammasome in THP-1 cells in response to adenovirus (positive control), ssAAV2-GFP, or scAAV2-GFP.