Viral vector technology for cell type specific gene delivery

Project Summary Gene therapy is a promising treatment for many diseases. For gene therapy to become increasingly successful, three hurdles must be overcome: We need viral vectors that are (1) safe, (2) efficient, and (3) cell type specific. Adeno-associated virus (AAV) has emerged as a viral vector that is safe in humans, efficient at delivering transgenes to both dividing and arrested cells, and able to drive long-term expression. Unfortunately, the broad tropism of AAV is detrimental when gene delivery to specific cells (e.g., cancer) is paramount and ectopic expression in healthy cells or tissues poses a risk to the patient’s safety. We recently reported a working prototype of a novel configurable viral gene delivery technology. This technology consists of a capsid that we genetically engineer to express an adapter domain to which we covalently attach monoclonal antibodies to form antibody-AAV composites. AAV tropism is redirected toward the antibody’s cognate receptor, which is expressed on a targeted cell type, but not off-target cell populations. Here, we will take the next critical steps to build on this prototype and broaden the impact of our technology. We will improve composite-AAV formation efficiency and infectivity (Aim 1), comprehensively map additional engineerable capacity across AAV serotypes identify new capsid engineering strategies and enable machine- learning guided AAV design (Aim 2) and, as a proof of concept, determine target specificity and spread of AAV composites in vivo (Aim 3). The outcome of this work will be a validated viral vector platform technology that uses antibodies to target gene delivery to rationally identified cell types. This technology will enable fundamentally new gene therapy paradigms and, in the longer term, lead to new therapeutic approaches for inherited disorders and cancer.