Retroviral Vector Stability: Inactivation Kinetics and Membrane Properties

Abstract

Previous papers concerning the inactivation of retroviral vectors have focused either the kinetic aspects of the inactivation process or the factors affecting vector stability. The present work aims at bridging this previous knowledge by simultaneously studying inactivation kinetics and structural aspects of retroviral vectors. For this purpose, two human derived cell lines (TE Fly cells) producing retroviral vectors with amphotropic and GALV envelopes were used. Vectors with amphotropic envelope exhibit a higher stability than those with GALV envelope. Using an Arrhenius-like plot it was possible to observe two inactivation kinetic phases for amphotropic enveloped vectors but only one for GALV enveloped vectors. Electron Paramagnetic Resonance (EPR) results show that the production temperature exerts an important effect upon vector membrane rigidity, with a consistency between kinetic phase and membrane transition temperatures being observed.. Since cell and vector membrane physico-chemical properties are affected as a response to changes in culture temperature and medium composition, such changes can be used more prospectively to improve the stability of retroviral vectors.