Humoral responses to AAV8 capsid in HB dogs following liver delivery of AAV-cFIX-Padua. All 3 dogs were assessed for anti-AAV8 (A) IgG1 and (B) IgG2 antibodies at baseline and time points following AAV administration using anti-AAV8 IgG ELISAs. Wick, black solid line, closed circles; Trex, black dotted line, closed circles; Wiley, solid gray line, open circles.