441. Direct Comparison of EF1α and PGK Promoters Reveals Superior Performance of the PGK Promoter for Expression of the Common Gamma Chain in a Canine Model of In Vivo Foamy Virus Gene Therapy for Severe Combined Immunodeficiency

Abstract

Foamy viruses (FV) are ideal vectors for in vivo gene therapy because FV infection is non-pathogenic in people, FV are more resistant to serum inactivation than lentiviruses packaged with the vesicular stomatitis virus glycoprotein (VSV-G), and FV exhibit favorable proviral integration patterns compared to gammaretroviruses. In vivo gene therapy with a FV vector expressing the human common gamma chain (γC) under the short EF1α promoter results in a functional immune reconstitution in X-SCID dogs.