Insect cell expression systems are widely used particularly for complex proteins, specifically recombinant protein production that require post-translational modifications similar to those found in mammalian cells. Insect cell lines are infected with recombinant baculoviruses to deliver the gene of interest and drive high-level protein expression.
The insect cell system is widely used in vaccine production – particularly for influenza and HPV vaccines – where the baculovirus-insect cell platform enables rapid and efficient protein expression. Structural biology research also relies on this system to produce large quantities of high-quality proteins for X-ray crystallography and cryo-electron microscopy studies.
How the Insect Cell Expression System Works
The insect cell expression system relies on the baculovirus expression vector system (BEVS) to produce recombinant proteins, including isotope-labeled variants. This system involves several key steps: baculovirus engineering, infection of insect cells, protein synthesis, and purification.
1. Baculovirus Engineering
The first step involves inserting the gene of interest into a baculovirus genome. This is achieved using recombinant DNA techniques, where the target gene is cloned under the control of a strong viral promoter, and the recombinant baculovirus is then generated either through homologous recombination in insect cells or through bacterial artificial chromosomes (BACs).
2. Insect Cell Infection and Protein Expression
Once the recombinant baculovirus is prepared, it is used to infect insect cell cultures grown in suspension using serum-free media. The virus hijacks the insect cells’ transcriptional and translational machinery to drive high-level expression of the recombinant protein. Labeled protein synthesis begins with the addition of stable isotope-labeled nutrients to the growth media. Labeled amino acids are incorporated directly, or are supplied as part of a pre-formulated stable isotope-labeled medium, allowing for efficient and direct incorporation into newly synthesized proteins.
3. Protein Folding and Post-Translational Modifications
Unlike bacterial expression systems, insect cells can perform complex post-translational modifications – including glycosylation, phosphorylation, and disulfide bond formation. These modifications ensure proper protein folding and functionality, making the system ideal for producing biologically active proteins.
4. Harvesting and Purification
Once optimal protein expression is reached (typically 48–72 hours post-infection), the cells are harvested via centrifugation, lysed, and the labeled proteins are purified using affinity chromatography. Mass spectrometry is then used to confirm the incorporation of stable isotopes, ensuring high-purity, labeled proteins suitable for structural and functional studies.
Advantages & Disadvantages of Insect Cell Expression Systems
Insect cell expression systems offer a unique balance between bacterial, yeast, and mammalian systems to provide a eukaryotic environment while maintaining relatively high protein yields. However, like any system, they come with both strengths and limitations:
| Advantages | Disadvantages |
| Eukaryotic Protein Processing – Supports post-translational modifications such as glycosylation, phosphorylation, and disulfide bond formation. | Technically Demanding Cultivation – Requires stable conditions and skilled handling; contamination or suboptimal growth can severely impact protein yield. |
| Proper Protein Folding – Reduces the risk of inclusion body formation, ensuring functional protein expression. | Longer Production Time – Typically takes 48–72 hours from infection to protein harvest, slower than bacterial systems. |
| High Expression Levels – Baculovirus-driven systems enable strong recombinant protein production. | Lower Yield than Bacterial Systems – Produces less protein per liter of culture compared to E. coli. |
| Scalability & Suspension Culture – Grows in serum-free suspension cultures, making large-scale production feasible. | Glycosylation Differences – While insect cells perform glycosylation, the structures differ from those in mammalian cells, which may impact functionality. |
| Lower Contamination Risk – Less prone to contamination by human viruses, improving biosafety for pharmaceutical applications. | Higher Cost than Bacterial Expression – Media and baculovirus preparation are more expensive than bacterial culture. |
Whilst a powerful tool for producing biologically active proteins with proper folding and modifications, these advantages come up against drawbacks including cost, yield, and processing time versus other expression systems.
Enhancing Your Protein Expression with Insect Cell Systems
At Silantes, we provide advanced insect cell expression systems utilizing baculovirus vectors for high-yield recombinant protein production. Our solutions support a wide range of research applications, featuring bio-based stable isotope-labeled solutions to further enhance your research capabilities. Explore our portfolio of insect cell expression products and services.
Not sure which system is right for your research? Contact us today, and our experts will help you find the best solution for your needs.
Silantes is currently developing a complex SF9 growth and protein expression medium. Contact us to be informed as soon as it becomes available.
Featured image: Harrison, R.L., Herniou, E.A., Jehle, J.A., Theilmann, D.A., Burand, J.P., Becnel, J.J., Krell, P.J., M. van Oers, M., Mowery, J.D., Bauchan, G.R., and ICTV Report Consortium, CC BY-SA 4.0, via Wikimedia Commons