Recombinant Bluetongue virus vaccines – or some, anyway

VIRUS-rota-200

General model of reo-like viruses. Copyright Russell Kightley Media

I picked up yesterday – via @MicrobeTweets’ Twitter feed – on a very useful list of papers in a “Virtual Special Issue” of Elsevier’s recent coverage of vaccines – for “World Immunization Week”. Great stuff, I thought to myself, as I browsed the list – and downloaded at least those that were Open Access, or which I can get via our Libraries’ IP range.

“Even better!”, I thought, as I saw a review entitled “Recombinant vaccines against bluetongue virus?”  A meaty, well-sourced review, I thought; good reading for me and my students / coworkers, and good meat for upcoming Introductions for papers yet to be written.  Indeed, it promised the following:

“The multiple outbreaks of BTV in Mediterranean Europe in the last two decades and the incursion of BTV-8 in Northern Europe in 2008 has re-stimulated the interest to develop improved vaccination strategies against BTV. In particular, safer, cross-reactive, more efficacious vaccines with differential diagnostic capability have been pursued by multiple BTV research groups and vaccine manufacturers. A wide variety of recombinant BTV vaccine prototypes have been investigated, ranging from baculovirus-expressed sub-unit vaccines to the use of live viral vectors. This article gives a brief overview of all these modern approaches to develop vaccines against BTV including some recent unpublished data.”

So, I parked the conveniently Open Access-ible window away on the side of my desktop, to be got back to with every expectation of delight.

Until I read it, that is: well-sourced it may be; excellent in its coverage, it is NOT.  In fact, apart from a brief discursion on subunit vaccines – concentrating almost exclusively on baculovirus / insect cell-produced proteins – it is almost exclusively concerned with live viral vectors for bluetongue proteins, and of poxviruses in particular.  Now, this is all very well, if that is what they work on – but to dismiss one of the potentially most exciting developments in recent Bluetongue vaccinology like this:

“VLPs of BTV have been also produced in plants recently using the cowpea mosaic virus and their use in a vaccination study produced no clinical manifestations in sheep after homologous challenge, although viremia was no [sic] evaluated (Thuenemann et al., 2013).”

– boggles the mind somewhat.  Really?  That’s all they have, compared to the screed immediately before it on baculovirus-produced antigens?  They get the expression system wrong – it is an Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana involving a Cowpea mosaic virus-derived enhanced translation vector – and neglect to mention that the VLPs produced are as good as anything produced in insect cells; will be FAR cheaper to produce, and WORKED AS WELL AS THE CONVENTIONAL ATTENUATED LIVE VIRUS VACCINE IN A CHALLENGE EXPERIMENT IN SHEEP.  True!

This is a big deal, folks, really: successful production of significant amounts of VLPs requiring simultaneous expression of 4 structural proteins of BTV-8 in plants AND their subsequent assembly, AND performing as well as the standard vaccine in an animal trial.  But no – not good enough for our review’s authors….

I must declare vested interests up front here: first, we work on plant-made recombinant Bluetongue vaccines; second, I and others in my group are co-authors of the paper whose lack of coverage I am aggrieved about.

But that’s not the point: what IS the point is that this review is a slipshod piece of work that damns our collective endeavour with faint praise, in community that might otherwise have been alerted to an alternative to the far-too-expensive-for-animal-use baculovirus expression technology.

Ah, well.  I suppose that’s what blogs are for B-)

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