A High-Multiplicity Baculovirus Method Enables Efficient Gene Delivery to Diverse Mammalian Cells In Vitro and to Multiple Organs In Vivo.

Recombinant baculovirus vectors are recognized as effective gene delivery systems for mammalian cells in vitro. However, their application in vivo has been limited due to inactivation by the host's complement system. We developed a recombinant baculoviral vector derived from Autographa californica multiple nucleopolyhedrovirus (AcMNPV), incorporating both CMV-IE and polyhedron promoter-driven green fluorescence protein (EGFP) (vAcMBac-CMV-IE-EGFP). We then evaluated the transduction efficiency and safety of vAcMBac-CMV-IE-EGFP at a high multiplicity of infection (MOI) across five distinct cell lines and in Sprague Dawley (SD) rats. In vitro, Sf9, HepG2, and Vero E6 cells showed high transduction rates (95.52 ± 4.86%, 80.53 ± 3.31%, and 80.87 ± 2.50%, respectively), significantly outperforming the other cell types tested, and cell viability remained largely unaffected even at an MOI of 1000. In vivo, EGFP expression was observed in the heart, liver, spleen, lungs, and kidneys of SD rats after tail vein injection. Direct injection of vAcMBac-CMV-IE-EGFP into the rat striatum also resulted in strong EGFP signals in neural tissues. These results demonstrate that a high-MOI baculovirus infection can serve as a remarkably efficient and versatile platform for gene delivery across diverse mammalian cell types as well as in various organs and neural tissues in animal models. This robust method might hold significant promise for future gene therapy applications.