Poly-L-lysine improves gene transfer with adenovirus formulated in PLGA microspheres

In vivo gene transfer with recombinant adenovirus vectors can be hindered b y the immunogenicity of the adenovirus capsid proteins. Previous work showe d that formulation of the vector with biodegradable polymers such as poly-l actic-glycolic acid (PLGA), polyethylene glycol (PEG), or lipids, may shiel d the virus from inhibition by neutralizing antibodies. Formulation of aden ovirus in PLGA microspheres also allowed for extended release in vitro. In experiments described here, we found that the surfactant used in the format ion of the primary emulsion could significantly improve the overall yield o f virus released. We also tested the effects of adding poly-L-lysine to ade novirus before encapsulation with PLGA. Our results show that although PLL did not effect the yield of virus encapsulated or released from the microsp heres, it significantly improved the efficiency of gene transfer after rele ase from the polymer.