Negative-strand RNA viral vectors: Intravenous application of Sendai virus vectors for the systemic delivery of therapeutic genes

Treatment by gene replacement is critical in the field of gene therapy. Suitable vectors for the delivery of therapeutic genes have to be generated and tested in preclinical settings. Recently, extraordinary features for a local gene delivery by Sendai virus vectors (SeVV) have been reported for different tissues. Here we show that direct intravenous application of SeVV in mice is not only feasible and safe, but it results in the secretion of therapeutic proteins to the circulation, for example, human clotting Factor IX (hFIX). In vitro characterization of first-generation SeVV demonstrated that secreted amounts of hFIX were at least comparable to published results for retroviral or adeno-associated viral vectors. Furthermore, as a consideration for application in humans, SeVV transduction led to efficient hFIX synthesis in primary human hepatocytes, and SeVV-encoded hFIX proteins could be shown to be functionally active in the human clotting cascade. In conclusion, our investigations demonstrate for the first time that intravenous administration of negative-strand RNA viral vectors may become a useful tool for the wide area of gene replacement requirements.