(310c) Targeting Lentiviral Vector to Specific Cell Types Via Single Chain Antibody

Viral gene therapy remains one of the most commonly used techniques today in the field of gene therapy. One of the key factors in improving the safety and efficacy of gene therapy is to design viral vectors that only target cell types of interest. However, most current techniques require the manipulation of the viral glycoprotein which leads to decrease in efficiency. We recently developed a novel technique to uncouple the function of viral glycoprotein into two distinct proteins, an antibody that will recognize the cognate antigen and a fusogenic molecule that will fuse with the endosome compartment thereby releasing the viral core in response to a decrease in pH. In order to improve our targeted transduction efficiency, we further engineered the fusogenic molecule to retain the fusogenic activity at a wider pH range and found a dramatic improvement in our targeted transduction efficiency. In this report, we focused our study on the anti-CD20 antibody, which is the other key parameter on our viral surface required to induce a successful targeted transduction. Two versions of single chain antibody were generated to pair with our existing engineered fusogenic molecules and were able to bind and transduce CD20-positive cells. Upon further investigating the properties of the single chain antibodies, we discovered that the transmembrane domain was important in both displaying and incorporating the antibody molecule onto the viral vector.