The threat of newly emerging pandemic influenza strains, and limitations of egg-based culture, has driven the need for rapid response manufacturing methods. Researchers from Austria believe they have developed an approach that could satisfy this demand.
In a paper published online on 29 December in Biotechnology Journal the researchers detail why they believe insect cell derived influenza virus-like particles (VLPs) “are a very fast, safe and effective alternative vaccine approach”.
Using two insect cell lines, namely Sf9 and BTI-TN5B1-4, the team was able to produce the first batch of VLPs 51 days after cloning work began. Accounting for an additional two weeks of gene synthesis, vaccine production of a new influenza subtype could start less than 10 weeks after isolating the RNA sequence.
In earlier work published in The New England Journal of Medicine Baxter claimed it could produce a H5N1 vaccine within 12 weeks of an outbreak. This used African green monkey kidney cells and the Austrian researchers draw parallels between mammalian and insect cell culture.
Both techniques offer fast production but notably the systems differ in the way they perform complex glycosylation. However, there have been no reports that this negatively impacts on the immunogenicity of products manufactured using either method.
Advantages of BTI-TN5B1-4
In tests on mice the Austrian researchers claim the VLPs they produced from both insect cell lines induced high titers of neutralising antibodies, leading them to believe that the vaccine could be effective.
Although both cell lines quickly produced effective VLPs the researchers believe BTI-TN5B1-4 has advantages over Sf9, in part because it decreases protein and baculovirus background. This reduces DNA contamination in BTI-TN5B1-4.
Furthermore, cells derived from BTI-TN5B1-4 are used in the production of GlaxoSmithKline’s Cervarix [human papillomavirus (HPV) bivalent (types 16 and 18) vaccine, recombinant].
Cervarix has been approved by the European Medicines Agency (EMA) and US Food and Drug Administration (FDA), establishing a regulatory precedent for therapeutics made using BTI-TN5B1-4.