AAV-mediated expression of a SARS-CoV-2 neutralizing antibody in monocyte-derived dendritic cells and human airway epithelial cells.

Abstract

Monoclonal antibodies (mAbs) offer potential for treating pulmonary infections but typically require high-dose intravenous delivery due to poor diffusion from the bloodstream to the respiratory epithelium. Here we evaluated adeno-associated virus (AAV) vectors to enable full mAb expression in human respiratory cell subsets. In A549 human lung carcinoma cells, which model alveolar type II (ATII) pneumocytes, the engineered AAV6.2FF vector demonstrated superior transduction efficiency compared to the parental AAV6. A single AAV6.2FF vector encoding both the immunoglobulin heavy and light chains linked by a P2A self-cleaving peptide (HC-P2A-LC) produced higher IgG1 levels than co-transduction with separate heavy and light chain vectors (HC + LC). In human monocyte-derived dendritic cells (moDCs), AAV6.2FF-HC-P2A-LC driven by the SFFV promoter induced sustained expression of a SARS-CoV-2 neutralizing IgG1. Efficient transduction and high-level mAb expression were also observed in primary human ATII organoids and lung fibroblasts. In contrast, air-liquid interface (ALI) cultures of differentiated airway epithelial cells showed lower, but stable, IgG1 expression that reduced SARS-CoV-2 propagation. These findings qualify AAV6.2FF as a promising platform for localized mAb expression in the human respiratory tract.