Baculovirus-mediated gene transfer into mammalian cells

Area of Science:

• Molecular Biology
• Virology
• Gene Therapy

Background:

• Baculoviruses, such as Autographa californica multiple nuclear polyhedrosis virus (AcMNPV), are insect-specific viruses.
• Gene delivery into mammalian cells is crucial for research and therapeutic applications.
• Developing efficient and specific gene delivery vectors remains a significant challenge.

Purpose of the Study:

• To evaluate the potential of a modified AcMNPV as a gene delivery vector for mammalian cells.
• To assess the efficiency of AcMNPV-mediated gene transfer in various mammalian cell lines, particularly liver cells.
• To investigate the mechanism underlying gene expression in target cells.

Main Methods:

• A modified AcMNPV carrying the Escherichia coli lacZ reporter gene was constructed.
• The modified baculovirus was used to infect human liver cell line HepG2 and primary rat hepatocytes.
• Gene expression (beta-galactosidase activity) was analyzed in infected cells post-infection.

Main Results:

• High-level lacZ expression was observed in >25% of HepG2 cells.
• Over 70% of primary rat hepatocytes showed beta-galactosidase expression.
• Expression levels varied significantly across different mammalian cell types, with liver cells being most susceptible.
• The block to expression in non-liver cells was post-entry, not due to internalization failure.
• lacZ expression onset was within 6 hours and peaked at 12-24 hours post-infection in HepG2 cells.

Conclusions:

• AcMNPV serves as an effective gene delivery vector for primary liver cells and HepG2 cells.
• The insect-specific nature of AcMNPV prevents replication in mammalian hosts, enhancing safety.
• AcMNPV's capacity for large inserts and efficiency in hepatocytes positions it as a valuable tool for liver cell genetic manipulation.