In vivo neutralization of AAV9 by anti-AAV9 monoclonal antibodies. (A to C) Neutralization profiles of anti-AAV9 monoclonal antibodies in the (A) spleen, (B) heart, and (C) liver. The anti-AAV9 antibodies tested here are ADK9, HL2368, HL2370, HL2372, and HL2374, with ADK4 (anti-AAV4) as a negative control. ADK9, HL2370, and HL2372 are neutralizing to AAV9 in the tissues tested, however; HL2374 is nonneutralizing in the spleen. HL2368 is nonneutralizing in all tissues tested.