Posts Tagged ‘vaccines’

PBVAB 5 Part 2

28 June, 2013

Session: Vaccines 1.

This session produced some of the most interesting talks of the conference, so I will go into some detail in describing them.

Charlie Arntzen (ASU, Tempe, AZ) gave a typically excellent presentation on their latest work on norovirus vaccine formulation for stability and oral delivery – using lyophilized aloe gel-derived nanoparticles.

Norovirus outbreaks are tracked by a CDC lab continuously; every 2 years or so new strains circulate, meaning vaccines will have to keep up.  Ligocyte makes VLPs in insect cells currently; however, plant expression has been shown to be able to respond quickly to strain changes, via Icon vectors used at KBP, with the possibility of very quickly making a lot of product.  Downstream formulation has been a problem, however, as the processing throws away lots of antigen protein downstream.

Ligocyte use MPLA and chitosan (an irritant) for nasal immunisation: this has 50% efficacy.  The FDA does not like adjuvants for nasal dosing – so they went for no adjuvant, and chose the nasal route as one gets a more uniform response for 5x less Ag than with oral administration.  The formulation is basically of VLP preparations with lyophilized and milled pectin content from aloe gel: the uniformly-sized nanoparticles absorb water, and stick to each other and to the nasal mucosa for 3 hrs+.

Charlie commented that “This is the one time I recommend putting white powder in your nose!”.

They have tried mixing VLPs of different virus types – and found that with 50 ug of each, you get same immune response as to one.  Apparently this virus is unusual as you can do virus challenge experiments quite easily: these cost $15K/patient, which is a bargain.  The group is looking at annual or biannual dosing for maximum protection, and is also formulating VLPs for oral vaccination.  Interestingly, the aloe gel also works for intramuscular vaccination – possibly as a result of a depot effect?

 

Yuri Gleba (Nomad / Icon Genetics, Halle, Germany) was supposed to speak on “Technology progress in PMP (=plant-made pharma) research” – but basically said “Transient technologies are the future!”, and then went on to demonstrate it.  He noted that KBP can process 1.2 tonnes biomass/day for agroinfiltrating plants, using a robot from a car factory and a converted industrial autoclave – and consequently have to grow plants in trays for infiltration. Nomad had therefore started investigating how spraying Agrobacterium onto plants might work – with a biosafe Agrobacterium as a prime requirement.  They also took the bold approach of doing transient agronomic trait engineering – for traits such as flowering control, drought tolerance, yield suites, cellulases and anti-microbials – and sold the idea to Bayer Crop Science.

Their technique uses an engineered Agrobacterium that is 100-1000x more efficient at gene delivery than standard strains, with surfactants that allow easy penetration of the leaf tissues.  In combination with the use of replicating vectors that spread cell-to-cell, they could get 100% of standard infiltration yields, by a far easier and much more scalable technique.  They found that spraying worked for most dicots and even for maize, albeit inefficiently, and that they could repeatedly dose plants for the same trait with no apparent harm.  Transient expression of cry1ab and cry2ab Bt toxins delivery worked well, as did delivery of the Cold Shock protein from B subtilis, which also works for drought tolerance.

Their technique does away with need for seed – they can do somatic trait addition / subtraction, they can use the technology outdoors, and there is no trait transmission and so no escape, as the genes do not get into seed.  It means they can produce proteins in  plants at commodity agricultural prices – which considerably broadens the scope of “biofarming” in terms of what products can viably be made!!

One good example was cellulases for bioethanol production: one needs 1-3% w/w relative to cellulose mass, meaning production must be high volume and cheap.  Yuri noted it was possible to store biomass as silage or possibly by vacuum-packing at room temperature for months and that the silage process also eliminated Agrobacterium.  He mused that it might be possible to make a sauerkraut-type oral formulation for recombinant protein delivery…B-)

As for antimicrobials in plants, he said organic crops have more microbes than standard, eg: the recent fatal infections caused by E coli in bean sprouts in Europe – and that a solution would be to make eg colicin E1 in the plants, to kill the bacteria in situ.  One can apply for GRAS status which is MUCH faster than for other routes of approval.  They were currently doing this for phage lysins, bacteriocins, and thaumatin, among others.  Yuri said transient expression tech was like flash drives vs old-style PCs: a versatile set of tools vs a one-trick pony.  He also mused that the technology could lead to reinvention of the old ideal of use of biofarming in undeveloped communities – presumably for low-cost remedies as well as for therapeutics, etc.

To a question on what was the shelf-life of recombinant Agro he replied that there was already field use of live bacteria to combat pathogenic strains; that one can take a Petri dish and dilute in 100l water and spray, and then keep the suspension for two days…it was a very robust bug!  An interesting regulatory point that came up was that the USDA thinks a plant is a GMO even if it is transiently sprayed.

 

Andres Wigdorovitz (INTA, Buenos Aires, Argentina) spoke on their experience of a decade’s worth of work on plant-made veterinary vaccines.  He opened by noting that he has a major problem of getting money from companies in Argentina – partly die to what a “product” is defined as, because what happens is that a “researcher has an egg, whereas the company wants a butterfly”.

They made the decision to work in platforms – to make diagnostic kits initially, which teaches one how to make recombinant proteins.  They use baculovirus/insect cells and plants – in the form of transgenic alfalfa or transplastomic tobacco – to make the same proteins for comparison purposes, and as products, depending on which was more suitable.  While they had had considerable experience with FMDV vaccines made in plants, which had been protective, their current work focused on making novel vaccines and products.  An example was camellid-derived VHH nanobodies – and the fact that fusing the E2 protein of Bovine viral diarrhoea virus (BVDV) with a anti-E2 VHH gave a better alfalfa-produced immunogen for something that was already protective.  Their experimental vaccine was better than the commercial vaccine from the Ab response – and they could get total protection with 3 ug vaccine, and even better efficacy if they made an E2-HLA fusion.  He believed they will have a commercial vaccine in less than 2 yrs as they were engaged in getting regulatory approval now.

In other work, a FMDV VP1 peptide-GUS fusion expressed 10x better in transplastomic tobacco than in transgenic alfalfa.  A rotavirus VP8* fusion protein was also 10x increased in chloroplasts, and dry leaves preserved the protein very well.  They were also making VHH nanobodies against human rotavirus as vaccine coverage of local strains was not good – and VHH against the conserved VP6 could penetrate the outer capsid and bind and neutralize infectivity whereas larger proteins did not work.  They got 3% TSP expression in tobacco chloroplasts.  They were also making VHH to other rotavirus proteins, and to human noro- and influenza viruses.  All in all, it was a very heartening demonstration of a good business model, and that developing countries too can lead the field in some respects.

 

The remainder of the session was taken up with two talks from our group: these were given by Drs Ann Meyers and Inga Hitzeroth, on the parrot-infecting Beak and feather disease virus CP-elastin fusion protein production, and Human rotavirus CP and VLP production in N benthamiana via agroinfiltration, respectively.

The BFDV work has just been published with MSc student Lucian Duvenage as first author – from PubMed, then:

J Virol Methods. 2013 Jul;191(1):55-62. doi: 10.1016/j.jviromet.2013.03.028. Epub 2013 Apr 9.
Expression in tobacco and purification of beak and feather disease virus capsid protein fused to elastin-like polypeptides.
Duvenage L, Hitzeroth II, Meyers AE, Rybicki EP.
Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7700, South Africa.

Abstract

Psittacine beak and feather disease, caused by beak and feather disease virus (BFDV), is a threat to endangered psittacine species. There is currently no vaccine against BFDV, which necessitates the development of safe and affordable vaccine candidates. A subunit vaccine based on BFDV capsid protein (CP), the major antigenic determinant, expressed in the inexpensive and highly scalable plant expression system could satisfy these requirements. Full-length CP and a truncated CP (ΔN40 CP) were transiently expressed in tobacco (Nicotiana benthamiana) as fusions to elastin-like polypeptide (ELP). These two proteins were fused to ELPs of different lengths in order to increase expression levels and to provide a simple means of purification. The ELP fusion proteins were purified by inverse transition cycling (ITC) and it was found that a membrane filtration-based ITC method improved the recovery of ΔN40 CP-ELP51 fusion protein relative to a centrifugation-based method.

Essentially, Lucian managed in some very elegant work to show that BFDV CP fused to a 51-mer ELP allowed production and subsequent simple purification of quite high yields of fusion protein.  It remains to be seen how immunogenic or protective this is – however, it is a breakthrough, as expression of the CP alone has been VERY problematic, in everything from insect cells through E coli, to plants.

Inga spoke on our recent MSc student David Mutepfa’s work on expression in plants of the CPs of a South African rotavirus that is not well matched to current live attenuated vaccines.  The short story is that he succeeded very well indeed in expressing three of the four proteins.  From a recent publication from me and Nunzia Scotti on plant-made VLPs, then:

Current studies in the Rybicki laboratory have focused on expression of capsid proteins of a local isolate of human rotavirus (G9 P[6]) that is not well matched to available commercial vaccines.  Expression of VP2, VP4 and VP6 in N. benthamiana was targeted via co-agroinfiltration to the cytosol, endoplasmic reticulum, apoplast and chloroplast. Electron microscopy showed that co-expressed VP2/6 and VP2/6/4 produced virus-like particles in the cytosol, with yields as high as 1.1 g/kg of plant material, for batches of 100 g.

…with a picture to prove VLPs are made:

rota pic

 

Rotavirus VP2/6/4 co-expression in N benthamiana: protein ex- tract partially purified by sucrose gradient centrifugation, particles captured onto electron microscope grids with mouse-anti VP6 antibody. Bar = 200 nm

Vaccines: a simple message

28 February, 2013

+MaryMangan over there on Google+ made an interesting point about simple messages to refute the kinds of nonsense promulgated by vaccine denialists, among others.

Here’s my contribution:

Vaccines!

Vaccines!

TMV in mouse lungs: more thoughts and refutations

13 February, 2013

tmv sedimhave been thinking about this paper (see last post), and it and other people’s posts (eg: Tommy Leung’s) have prompted more response.

I note the authors  say the following:

“There is other published literature that challenges the dogma of the strict boundaries between plants and vertebrates for viruses. In non-vertebrate animals, it was shown that plant pathogenic viruses displayed complex interactions with insects, and the transcription and replication of some plant viruses within insects was described [29][32]. In addition, in some cases, insects were found to be affected by plant viruses [33]. Furthermore, it was recently shown that Tomato spotted wilt virus (TSWV) could infect two human cell lines, HeLa and diploid fibroblasts, depending on the expression of a viral polymerase-bound host factor[34]. Additionally, despite plant virus replication was not observed in animals, Cowpea mosaic virus (CPMV), a plant comovirus in the picornavirus superfamily, was able to bind and enter mammalian cells, including endothelial cells, and the binding protein for the virus was identified as a cell-surface form of the intermediate filament vimentin [35]. Furthermore, CPMV was found to persist for several days post oral or intravenous inoculation in a wide panel of body tissues in mice, including in the lung and the liver [36]. Additionally, it was demonstrated that TSWV induced a strong immune response in its insect vector Frankliniella occidentalis [37] and that oral administration of Cowpea severe mosaic virus, Alfalfa mosaic virus and chimeric plant virus particles induced a durable and systemic immune response in mice [38][39]

Yes.  Um. Well.  The “dogma of the strict boundaries between plants and vertebrates for viruses”?  I have been teaching virology for 32 years, and I am not aware of actual DOGMA – as in, “that which has to be believed”.  Rather, there has been the cumulative set of OBSERVATIONS that nothing that anyone has ever isolated out of a plant – and that replicates in it – has infected a vertebrate.  I make that distinction, because there is always the possibility that, as we and others have found with insect viruses, plants can act as a “circulative, non-propagative vector” for insect viruses (for Rhopalosiphum padi aphid virus in barley, from my lab, and Leafhopper A virus in maize) – and if one realises that male mosquitoes, and often also females, feed on plants…you see where I’m going here?  As in, it might well be possible for a virus that multiplies in an insect and also in a vertebrate, to POTENTIALLY be found in a  plant?

In ay case, this is largely beside the point, because the authors get sidetracked into discussing Tomato spotted wilt – which happens to be a plant-adapted bunyavirus, most closely related to insect and vertebrate phleboviruses – “depending on the expression of a viral polymerase-bound host factor”.  Really??  And if it isn’t there?  Does the virus in fact spread?  For that matter, my lab has cell-free translated two aphid picorna-like virus genomes in rabbit reticulocyte lysates, but we made no claim that it could happen in rabbit cells.  Moreover, they make much of the fact that “a plant comovirus in the picornavirus superfamily, was able to bind and enter mammalian cells…[and] was found to persist for several days post oral or intravenous inoculation in a wide panel of body tissues in mice, including in the lung and the liver”.

Yes?  And?  A REALLY stable plant virus was able to bind and enter animal cells, and persist?  The problem with that is…?

We in the virus-like particle vaccine field RELY on the fact that VLPs will be taken up by cells of the immune system in vertebrates, and that they will elicit immune responses – so why is this regarded as a problem?  In fact, TMV has itself been tested as an RNA vaccine delivery system, due to its ability to protect a RNA payload, and get itself delivered into reticulocytes and macrophages – meaning this property has been known for some time, and has not hitherto been seen as a problem!

I think these authors have hyped something that is quite interesting into what THEY regard as a potential problem, for the purposes of getting their article accepted – and I think this needs to be recognised, and that the perceived risks need to be minimised by the knowledgeable.

PLOS ONE: Tobacco Mosaic Virus in the Lungs of Mice following Intra-Tracheal Inoculation

13 February, 2013

See on Scoop.itVirology News

“Plant viruses are generally considered incapable of infecting vertebrates. Accordingly, they are not considered harmful for humans. However, a few studies questioned the certainty of this paradigm. Tobacco mosaic virus (TMV) RNA has been detected in human samples and TMV RNA translation has been described in animal cells. We sought to determine if TMV is detectable, persists, and remains viable in the lung tissues of mice following intratracheal inoculation, and we attempted to inoculate mouse macrophages with TMV. In the animal model, mice were intratracheally inoculated with 1011 viral particles and were sacrificed at different time points. The virus was detected in the mouse lungs using immunohistochemistry, electron microscopy, real-time RT-PCR and sequencing, and its viability was studied with an infectivity assay on plants. In the cellular model, the culture medium of murine bone marrow derived macrophages (BMDM) was inoculated with different concentrations of TMV, and the virus was detected with real-time RT-PCR and immunofluorescence. In addition, anti-TMV antibodies were detected in mouse sera with ELISA. We showed that infectious TMV could enter and persist in mouse lungs via the intratracheal route. Over 14 days, the TMV RNA level decreased by 5 log10 copies/ml in the mouse lungs and by 3.5 log10 in macrophages recovered from bronchoalveolar lavage. TMV was localized to lung tissue, and its infectivity was observed on plants until 3 days after inoculation. In addition, anti-TMV antibody seroconversions were observed in the sera from mice 7 days after inoculation. In the cellular model, we observed that TMV persisted over 15 days after inoculation and it was visualized in the cytoplasm of the BMDM. This work shows that a plant virus, Tobacco mosaic virus, could persist and enter in cells in mammals, which raises questions about the potential interactions between TMV and human hosts.”

Ed Rybicki‘s insight:

Interesting paper!  Which proves…which proves…which proves TMV is seriously resistant to degradation in animals and in mammalian cells; that it can enter macrophages; and that it…what?  What, exactly, are the “…questions about the possible interactions…”?  What would TMV do in mammalian cells?  Yes, it might be uncoated and be translated; it is far less likely that it MIGHT be able to replicate its RNA – and then?  While it can apparently be taken up quite efficiently by macrophages – a property which, incidentally, has led to its being trialled as an RNA vaccine delivery system – this is a dead end, and one that is quite normal for particles of any kind being introduced into mammals.

Which is something that happens every day, as we and our cousin mammals eat: it has been shown elsewhere that animals are actually quite good spreaders of plant viruses, some of which – like TMV and the even tougher Cauliflower mosaic virus – pass right through at high survival rates, and remain infectious.  We will all probably have eaten many grams of various viruses in our lives, and derived nothing more than nutrition from them.

I also remember, even though it was very late at night, 31 years ago, and in a bar in Banff in Canada, a conversation with one Richard Zeyen.  He told me they had used ELISA to test everyone in their lab for antibodies for TMV, seeing as they worked with it, and had newly developed a test.  And everyone was immune – presumably, to aerosolised TMV that had been breathed in or otherwise ingested.  Proving…that oral vaccines based on TMV could work, and that most of us are probably immune to all sorts of viruses that don’t replicate in us – and nothing more!

Including, in the case of many people in the Eastern Cape Province of South Africa, sampled by one Don Hendry via the local blood bank, to a virus of Pine Emperor moths – because it multiples to such high levels in its host that anyone walking in the pine forests was bound to be exposed via the environment.

So this is an interesting paper – and no more.  It will, of course, lead to alarmist articles and blog posts, and people calling out for urgent surveillance of food, in which people will find many viruses.  And so what?  They have been with us for as long as we have been eating plant-derived food, and have NEVER been associated with any disease, transmissible or otherwise – so my best advice is that we ignore them.

See on www.plosone.org

Second Workshop on Molecular Farming in Australia

15 April, 2010

I was privileged to attend – and give the first presentation in – this workshop, on April 12-13 this year, at Monash University’s Clayton Campus in Melbourne. While it was small – about 25 people all told – I think what was discussed was very interesting. Even more interesting was the discussion of where the technology should be taken in Australia, given the science environment there has many similarities to the South African situation.

The workshop included some 20-odd people, mainly from the School of Biological Sciences at Monash in Melbourne, but with representation from  the University of Cape Town, Southern Cross University (NSW), the Agri-Science in Queensland, the University of Queensland, and –importantly for the implications of this kind of work – the Australian Department of Defence.

I kicked off proceedings with a Keynote Address on “Viruses, vaccines and plants:  The Cape Town experience”: this was essentially an account of my laboratory’s work on plant-made vaccines and other pharmaceutically-important molecules over the last 15 years, focussing on optimisation of expression of relevant molecules, and our work on Human papillomavirus (HPV), HIV and influenza virus vaccines in particular.  I emphasised that optimisation requires one to look at molecule, gene, vector, expression host, expression modality and intracellular localisation – and that there was no substitute for an empirical determination of optimisation parameters.

In the first session – Plant-Made Vaccines – chaired by Diane Webster of Monash, Sadia Deen of Monash described her work on making an experimental mouse vaccine against the causative agent of fowl cholera,  Pasteurella multocida.  Expression of the OmpX protein via transient agroinfiltration of N benthamiana was successful, as was protection of mice against lethal challenge by injection of freeze-dried leaf powder with alum as adjuvant.  Interesting features for me were that the vaccine was apparently better than the E coli-produced version, and that it was apoplast-targetted – meaning purification could be very simple.

Assunta Pelosi of Monash then described an investigation of the in vivo fate in mice of the B subunit of the E coli enterotoxin (LTB) that had been produced in plants and then and formulated in different ways.  Hairy root culture-produced protein was most protected and released antigen latest regardless of formulation; otherwise, LTB produced in N benthamiana leaves or tomato fruit was released in stomach or duodenum if formulated in aqueous (=apple juice + honey) media, and in the duodenum and ileum if formulated in lipid (=peanut butter) media.  There seemed to be no difference in how much LTB went all the way through the animals regardless of origin or formulation.  I was interested in the possibility of an enhanced adjuvant effect with protein produced in N benthamiana compared to other routes of production, as this has been documented for other proteins – and this is apparently being investigated, using protein produced in different Nicotiana spp.

Session 2 – Plants as Production Systems – was chaired by me, and featured a fascinating mix of production of an exciting new product, a chemical engineering view of production of antibodies via plant tissue culture, and  an introduction to the very significant industrial potential of sugarcane and/or sugarcane processing infrastructure for biopharming.

Diane Webster of Monash described her group’s work on expression of soluble human-derived RAGE, which has potential both as a diabetes therapy to lessen uptake by the ordinarily membrane-linked receptor of advanced glycation end-products (AGE), and as a reagent for advanced assay techniques.  She described how the Ig-like protein was very difficult to make in insect cells, and how the E coli or yeast-made versions were useless because of lack of or inappropriate glycosylation.  sRAGE could be made successfully in plants; addition of a KDEL ER retention signal adversely affected yield, while a His-tag did not.  While yield was only ~0.6% of total soluble protein (TSP), they could get 70% recovery of a 90% pure protein – which was identical to mammalian RAGE in terms of –S-S- bridges and functionality as assessed by surface plasmon resonance.  It was interesting that use of ICON vectors did not appear to help increase yield.

Pauline Doran, of the Dept Chemical Engineering and the School of Biological Sciences at Monash, gave a fascinating account of her experiences with plant tissue culture as a production vehicle for biopharming.  Her first point was that there are important trade-offs with bioreactor vs. whole plant production: for example, production of biomass was more expensive for the former, but purification of final product was probably cheaper.  It was also much easier and more reproducible to control a wide variety of environmental and growth conditions for tissue cultures.  She described years worth of experience of making anti-S mutans monoclonal Abs in transgenic suspension cultured tobacco cells, shooty teratomas derived from transgenic plants using Agrobacterium tumefaciens, and hairy root cultures produced via A rhizogenes transformation.  Production over years was most consistent for root cultures, while levels of mAb production were similar initially for roots and suspension cultured cells.  An important consideration in how to make the Abs was that suspension cultured cells produced significant amounts of proteases via the apoplast, so that secreted Abs could be degraded – which is why it was better to retain them in the ER.  Rhizosecretion form root cultures was a useful means of production; however, adsorption to vessel walls was a major problem even though it could be blocked using proteins or PVP.  The talk was valuable for laboratory-end scientists because it showed up practical problems – and solutions – not often dealt with during the research and development phase of biopharming research.

Peter Twine of the Queensland CRCSIIB recounted how they had been given Aus $28 million over 7 years to improve value in sugar in Australia.  He noted that Australia could handle 40 million tonnes of cane in some 40 processing stations annually – so very little further investment would be needed to get much more product than the bagasse, sugar and ethanol that the crop was presently used to produce.  In terms of biomass, a cane field could produce 50-100 tonnes / ha / yr, which could be significantly improved by strategic backcrossing.  Value enhancements which had already been made included production of Barrecote – a biodegradable waterproof coating for recyclable paper – as well as a GI-lowering agent, and PHB (for production of plastics) that was 3-4 times cheaper than E coli-produced material.  He said what was wanted for sugarcane was an Agrobacterium transformation protocol, as well as chloroplast transformation: this would allow significant expression enhancement as well as reliable transgenesis.  The talk was valuable both as an informational window into a well established industrial-scale biotechnology, and as a window into possibilities for use of the established biomass processing infrastructure for biopharming purposes: for example, discussion after the talk ranged around the significant potential for use of even only a small fraction of that infrastructure – for example, one processing mill – to produce potentially very large amounts of lower-end pharmaceuticals (high volume, low cost), such as enzymes or nutraceuticals.

The last Monday session was a Student Forum, chaired by Rob Shepherd from Monash.  Giorgio De Guzman (Monash) described how their team had systematically investigated production of LTB in hairy root cultures of tobacco, tomato and petunia: he mentioned that a distinct advantage of hairy root cultures was that they grew rapidly, and required only simple media with no hormones.  They showed that tobacco and petunia cultures gave the best yields (60-70 ng/g root), and that while there was some negative correlation of growth with expression level, this was least for petunia.  Optimum growth of cultures was reached after 22 days, and rhizosecretion peaked at 20 days.  What was most interesting to me was that it was possible to regenerate plants from root cultures: this would allow seeding and preservation of good producer lines as seed rather than as root cultures, with the option or re-establishing root cultures again as needed.  An added bonus was that such cultures seemed to grow better than the original cultures, with the same recombinant protein yield.

Huai-Yian Ling (Monash) gave a talk on a topic close to my heart: this was the use of plants to produce candidate pandemic influenza virus vaccines.  She specifically addressed the potential problem for oral vaccine development of the high alkaloid content of the tobaccos that are otherwise very well suited for pharming, due to their ease of propagation, high biomass per plant, and prolific seed production, by crossing transgenic H5 haemagglutinin (HA)-producing N tabacum with a N glauca line in which alkaloid production had been silenced by siRNA.  She determined that a plant codon-optimised HA gene expressed best, and gave 13 ug/g leaf tissue in the line used for crossing.  The hybrid progeny had no alkaloid, but also only produced HA at levels <1 ug/g.  Lyophilisation allowed this to be concentrated to 64 ug/g, which would be sufficient for oral immunisation experiments.  She planned to see whether a LEA protein from a resurrection plant would protect the HA.

The final talk – and of only two in the whole workshop which did not involve transgenic plants or recombinant protein expression – was by Sylvia Malory (Southern Cross Univ).  She had studied the possibility of “mining” rice domestication genes in the rice relative Micolaena stipoides: this grass is a drought-, frost- and shade tolerant perennial which produces rice-like seed.  Her approach was to exploit the extensive sequence and map databases for rice and other grasses so as to rapidly extract relevant genetic information for homologues of important rice genes from whole-genome shotgun sequencing runs of M stipoides DNA.  Traits of interest included reduced plant height, non-shattering seeds, increased yield, controlled seed dormancy, photoperiod insensitivity, drought tolerance and disease and insect tolerance.  For me the interest in this talk was that the potential for crossover between the biopharming and crop improvement spheres seems to get closer and closer with improvements in technology such as pyrosequencing, in that crop targets such as secondary metabolite engineering can also be exploited for pharming.

The final session of the Workshop on the Tuesday morning was left to me to summarise what the strategic directions of the existing and future “Molecular Farming Network” in Australia could be.  I approached the topic by summarising where I thought the biopharming field was presently in terms of direction and priorities – which was that the latter had shifted from the largely “vaccines in edible transgenic plants” hype of early years, to a more mature appreciation that transiently-expressed proteins in non-food plants were the way to go, and that the preference for products should be enzymes, reagents, diagnostics,  and then therapeutics, and animal vaccines – with human vaccines as a long-term goal.  This notwithstanding, I highlighted the fact that transiently-expressed plant-made candidate vaccines for H5N1 and H1N1 influenza and for noroviruses were probably the quickest emergency response vaccines ever made, which was a very important niche for the technology. 

My impression from the workshop, and from discussions with various folk, was that this particular biotechnology in Australia is presently under-developed, despite the presence in Australia (and apparently, mainly at Monash University) of considerable expertise and potential products.  I caution against the single-minded pursuit, for example, of “edible” or even of oral vaccines, where injectable versions may well work better and be cheaper to produce, simply because much less active ingredient is needed.  I also urge that the production of various reagent- or diagnostic-related products be pursued more vigorously, given that there is either no regulatory barrier to overcome, or – for animal products in particular – a far lower one than exists for products made for use in humans.

And I thank Amanda Walmsley, John Hamill, Rob Shepherd and Assunta Pelosi for looking after me so well.

Assunta and Ed at the MCG, watching Collingwood play Hawthorne in the AFL

The Melbourne Cricket Ground: awesome....


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