Mol Ther. 2025 Mar 8:S1525-0016(25)00177-7. doi: 10.1016/j.ymthe.2025.03.003. Online ahead of print.
ABSTRACT
Neutralizing antibodies (NAb) against adeno-associated virus (AAV) represent a significant obstacle to the efficacy of systemic recombinant AAV vector administration or re-administration. While there are some promising preclinical immunomodulation strategies in development, insights into which B cell subsets and compartments maintain persistent AAV NAb may define the optimal eradication strategy. Given the limited success of CD20-directed monotherapy in previous studies, we hypothesized that CD19-directed approaches that extend targeting into the plasma cell compartments may improve AAV NAb eradication. We tested this approach in mice using chimeric antigen receptor T cells (CAR-T) or monoclonal antibodies (mAb). We observed that combination mAbs targeting CD19, CD22, CD20, or B220 in mice did not eliminate tissue-resident B cells and, correspondingly, did not deplete pre-existing high titer AAV8 NAb. In contrast, CD19 CAR-T therapy eliminated peripheral and tissue-resident B cells and plasma cells and resulted in a marked reduction or eradication of high titer AAV8 NAb that permitted successful transgene expression following systemic AAV8 re-administration in mice. This successful therapeutic approach in mice identifies the population and location of B cells necessary to reduce or eradicate AAV NAb sufficiently to permit successful transgene expression with systemic AAV vector administration.
PMID:40057826 | DOI:10.1016/j.ymthe.2025.03.003
