Longevity of Infectious Budded Baculovirus Stocks

A question that comes up repeatedly is the long term stability of recombinant budded baculovirus stocks.  This is a particular issue now that most of them are generated using insect cells grown in serum-free medium.  It has long been a mantra in virology that you should always have a little bit of protein in your virus suspension to help stabilise the virion structure or prevent non-specific binding to glass or

Rapid Virus Titration by QPCR

Knowing the infectious titre of a recombinant virus stock is really important prior to testing for protein production in insect cells.  It enables you to add the optimal quantity of virus to initiate virus infection.  Too much virus and you are wasting your stock.  Too little virus and you won’t establish a synchronous infection.  For some proteins this may not matter, as the virus produced by the initial round of

Virus Like Particles VLPs for Therapeutics and Research

Oxford Expression Technologies (OET) is now able to apply its flashBAC™ baculovirus expression system to vaccine production, particularly in the exciting new field of virus like particle (VLP) vaccines. A virus like particle is an assembly of virus structural proteins that mimics the configuration of a real virus, except that it contains no genetic material. If a person is vaccinated with VLPs then an immune response is generated as if

Titrating Stocks of Recombinant Baculoviruses using the Plaque Assay Technique

We were going to devote this blog to a comprehensive account of how you might determine the infectious titre of your virus stock.  However, when our CEO got wind of this he started ruminating about how things were “back in the day” and how he had to collect seaweed from the seashore to extract agar for his overlays…!  No, we didn’t believe him either, but he is approaching his 7th

Production of High Titre Virus Stocks

In our last blog post we talked about the process of transfecting insect cells with virus DNA and how you could recognize success or otherwise.  Transfections are normally done on a fairly modest scale (2-5ml) in culture dishes.  Therefore your P0 virus stock is of low volume and probably modest infectious titre (107 plaque forming units [pfu] per ml or lower; we will discuss how to measure this value in

Transfection of Insect Cells with Baculovirus DNA

Independent of the method you use to produce recombinant viruses, at some point you have to transfect insect cells with virus DNA to reconstitute infectious virus particles.  When using the flashBAC™ system, you simply add it to your transfer vector containing the foreign gene and use a suitable transfection agent (e.g. baculoFECTIN II )to achieve entry of DNA into the cells.  The transfected cells are then incubated at 28°C for

To Heat Treat or Not to Heat Treat Calf Serum, that is the Question?

Ok, so the Bard is probably spinning in his grave at our blatant plagiarism of the script from the “Scottish Play” (it is bad luck to use its real name, apparently).  However, it seems an apt way to introduce the question of whether or not you should heat treat foetal bovine serum (FBS) before using it to propagate insect cells.  Of course, Spodoptera or Trichoplusia spp. cells are mostly grown

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