BaculovirusSystem

The baculovirus system, commonly referred to as the baculovirus expression vector system (BEVS), uses insect-infecting baculoviruses to produce recombinant proteins in cultured insect cells. The most frequently employed baculoviruses belong to the genus Nucleopolyhedrovirus, with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Bombyx mori nucleopolyhedrovirus (BmNPV) being the workhorses. Researchers create recombinant baculoviruses that carry the gene of interest under strong late promoters, such as the polyhedrin promoter, and infect insect cell lines like Spodoptera frugiperda (Sf9, Sf21) and Trichoplusia ni (High Five).

In BEVS, optional baculovirus shuttle vectors (Bacmids) enable cloning and recombination in Escherichia coli before producing recombinant virus in insect cells. Upon infection, the system drives high-level expression of the target protein, which can be directed to be secreted or retained intracellularly. The approach supports complex proteins and multi-subunit assemblies and often yields post-translational modifications that are closer to those of higher eukaryotes than bacterial systems.

Advantages of the baculovirus system include high expression levels, proper folding and assembly of many eukaryotic proteins, and compatibility with serum-free, scalable insect cell cultures. The system is generally considered safe for laboratory use because baculoviruses do not replicate in vertebrate cells and are not pathogenic to humans.

Limitations include differences between insect and mammalian glycosylation, which can affect some proteins intended for human therapeutics, as well as potential differences in post-translational processing. While highly versatile for research and production of many proteins and vaccines, the BEVS may require glycoengineering or alternative expression platforms for certain applications.