|Cas9-specific immune responses compromise local and systemic AAV CRISPR therapy in multiple dystrophic canine models.
|Year of Publication
|CH Hakim, SRP Kumar, DO Pérez-López, NB Wasala, D Zhang, Y Yue, J Teixeira, X Pan, K Zhang, ED Million, CE Nelson, S Metzger, J Han, JA Louderman, F Schmidt, F Feng, D Grimm, BF Smith, G Yao, NN Yang, CA Gersbach, S-J Chen, RW Herzog, and D Duan
Adeno-associated virus (AAV)-mediated CRISPR-Cas9 editing holds promise to treat many diseases. The immune response to bacterial-derived Cas9 has been speculated as a hurdle for AAV-CRISPR therapy. However, immunological consequences of AAV-mediated Cas9 expression have thus far not been thoroughly investigated in large mammals. We evaluate Cas9-specific immune responses in canine models of Duchenne muscular dystrophy (DMD) following intramuscular and intravenous AAV-CRISPR therapy. Treatment results initially in robust dystrophin restoration in affected dogs but also induces muscle inflammation, and Cas9-specific humoral and cytotoxic T-lymphocyte (CTL) responses that are not prevented by the muscle-specific promoter and transient prednisolone immune suppression. In normal dogs, AAV-mediated Cas9 expression induces similar, though milder, immune responses. In contrast, other therapeutic (micro-dystrophin and SERCA2a) and reporter (alkaline phosphatase, AP) vectors result in persistent expression without inducing muscle inflammation. Our results suggest Cas9 immunity may represent a critical barrier for AAV-CRISPR therapy in large mammals.