Nanotherapeutics-mediated tolerogenic induction for enabling adeno-associated virus vector gene therapy re-administration by overcoming anti-drug antibodies

Recombinant adeno-associated virus (AAV) vectors have become promising platforms to deliver therapeutic transgenes for the treatment of monogenic disorders. However, anti-AAV antibodies that are released by B cells after AAV treatment create a substantial barrier to their long-lasting safe and effective therapy, making AAV gene therapy a "one-shot" treatment. Herein, we developed tolerogenic nano-adjuvants (named RICP) composed of rapamycin (RAPA) and itaconate (ITA) to induce specific immune tolerance to overcome the anti-drug antibodies (ADAs). This strategy blocked the feedback loops of follicular helper T (Tfh) cells and germinal center B cells <i>via</i> metabolic regulation, complementary to the induction of regulatory T cells (Tregs) <i>via</i> mTORc1 inhibitor RAPA, consequently preventing the secretion of anti-AAV antibodies. The developed nano-adjuvants also significantly increased the expression of transgenes (such as luciferase, green fluorescent protein and human embryonic alkaline phosphatase reporter transgene) in the liver at re-dosing compared with mice treated with AAV alone, which showed almost no change in transgene expression. This emerging strategy provided an AAV re-administration schedule to not only mitigate toxicities with high vector doses but also re-store therapeutic benefits in children during significant cell proliferation.