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Plant-made vaccines and reagents for SARS-CoV-2 in South Africa

4 April, 2020

Plant-Made Vaccines and Therapeutics

I have published a number of reviews on plant-made vaccines (see below), and our Biopharming Research Unit (affectionately known as “The BRU”) has been very active in this research area for nearly twenty years now. The theme running through all our publications is always “Plants are a cheaper, faster, safer and more scalable means of producing pharmaceutically-relevant proteins than any of the conventional expression systems…” Since 2003 we have published 50-odd articles on plant-made recombinant proteins, including human and animal vaccine proteins and enzymes, so we have used this justification a lot.

Which begs the question, why isn’t Big Pharma using plant plant production, then?

After all, it’s been 30-odd years since the first “molecular farming” product was made, and many proofs of principle and several of efficacy of therapeutics and vaccines have been obtained, yet the pharmaceutical world has just two products that have been licenced or emergency licenced for use in humans. The first is Elelyso from Pfizer, better known in molecular farming circles as glucocerebrosidase developed by Protalix, which is an enzyme replacement therapeutic for persons suffering from Gaucher disease. This is not strictly speaking a plant product, though, as it is made in transgenic suspension cultured carrot cells, in 800 litre plastic bags.

The other is ZMapp, which is a cocktail of three “humanised” monoclonal antibodies (mAbs) which bind to Ebola virus, made by transient expression in Nicotiana benthamiana plants, and which were used in people as a post-infection therapy in the West African Ebola disease outbreak from 2014-2016.

If you consider that the first products to receive regulatory body approval – both in 2006 – were a mAb to hepatitis B virus surface antigen (HBsAg) that was used in purification by a Cuban company of the protein from yeast culture lysates, and tobacco suspension culture-produced Newcastle disease virus vaccine made for Dow AgroSciences that was never marketed, there has been effectively no market breakout at all for plant-made pharmaceuticals (PMPs).

Why is this? Why is it that a technology that can produce biomass containing product-of-interest between 100 and 1000 times more cheaply than mammalian CHO cells, or 10 – 100-fold cheaper than yeast or bacterial cultures, and be scaled from lab to industrial levels of production quicker than any other system, still languishing in the biotech industry doldrums?

Rybicki, 2009: Drug Discov Today. 2009 Jan;14(1-2):16-24. doi: 10.1016/j.drudis.2008.10.002

Granted, biomass production is only the upstream part of pharmaceutical production; the downstream purification / refinement / vialling and packaging costs for plant-made products will be the same as for conventionally-made versions, and these are typically much higher than biomass production costs. My own back-of-the-envelope calculations, done at a conference I attended where these costs were broken down by an industry expert, came out with plant-made finished product in a vial being 32% cheaper than the conventional equivalent. Given the large markup on finished product, this “advantage” is in itself not sufficient motivation for Big Pharma to change the means of production, given their typically enormous investments in stainless steel and other infrastructure.

And yet…doubling production capacity for any given product by a single Big Pharma supplier using conventional cell culture technology would entail spending the same amount again to get more stainless steel – which is typically multiples of at least US$100 million – as well as spending an inordinately long time getting the new plant certified. Also, even making a new product from scratch using existing infrastructure would involve heroic cleaning and rejigging of tanks and feed pipes and other paraphernalia used for biomass production, recertifications and the like, which could take months.  With plant-based manufacture, on the other hand, doubling production capacity means using double the number of cheaply-grown plants, possibly doubling the volume of Agrobacterium tumefaciens suspension to dunk them into, and then having enough space to put them under lights for 5-7 days or so, all with the same downstream processing capacity.

Then, there is the speed of scalability, which is unmatched for plant-made proteins. Consider this: given a ready supply of plants, it is theoretically possible for a molecular farming industrial facility to scale plant production of any given protein from lab bench scale – say a few milligrams/batch –  to industrial scale (kilograms per batch), in as long a time it takes to culture the few hundred litres of Agrobacterium you would need for infiltration. Keeping a large reserve of plants is cheap; commercial greenhouses could do this very cheaply – meaning biomass is effectively instantly available to whatever volume required. Culturing Agrobacterium to scale would also literally take a couple of days, meaning infiltrating and incubation for target molecule synthesis could take just a few days from obtaining a gene. Scaling a new line of stably transfected CHO cells from a flask up to 30 000 litres, on the other hand…this takes many cell doublings, with the attendant problems of maintaining both genetic integrity and sterility, and is far more expensive and takes longer.

Plant-Made COVID-19 / SARS-CoV-2 Vaccines

In fact, in 2012 as part of the DARPA “Blue “Angel” challenge, Medicago Inc. of Quebec in their new North Carolina facility, managed to make 10 million doses of H1N1 influenza virus vaccine as virus-like particles (VLPs), vialled and labelled, within a month of being given the sequence of the virus. If one considers that seasonal influenza vaccines take at least six months to make by egg culture, even with accelerated clinical testing and certification, this is a truly impressive improvement on current technology, and probably the quickest development of an influenza virus vaccine ever*. The company has since advanced to making and testing a quadrivalent seasonal influenza vaccine candidate through Phase III clinical trial, for imminent commercial release, was awarded “Best New Vaccine Technology/Platform” prize at the World Vaccine Congress in 2019 – and on March 12th 2020 announced they had made a viable vaccine candidate against COVID-19. They did this in just 20 days after receiving (presumably) the S envelope glycoprotein gene, and moreover made VLPs using their proprietary technology: VLPs are better immunogens than soluble subunit proteins, as they are much better at stimulating both antibody and cellular immune responses.

Virus-like particles made the same way Medicago will probably make SARS-CoV-2 VLPs – from this paper: https://zoom.us/j/313676518?pwd=bnFrQmxtR3l2TjY4VGFWWEhjZklnZz09

They are not alone in this space: just two weeks later, British American Tobacco (BAT) gained a lot of media attention when they also announced a candidate plant-made vaccine against SARS-CoV-2. While many hailed the repurposing of tobacco by a cigarette-manufacturing company as being an unexpected and good thing, it was really the BAT subsidiary RJ Reynolds’ recent purchase of Kentucky BioProcessing Inc, itself a spinout of one of the pioneering molecular farming companies (Large Scale Biology Inc., now sadly defunct) and the firm that had produced the largest amounts of the anti-Ebola ZMapp mAbs, that allowed them to take the credit. History aside, KBP announced they had “cloned a portion of COVID-19’s genetic sequence to create an antigen, which induce an immune response in the body” – which almost certainly means the S glycoprotein, or a portion of it – and that they could potentially make 3 million doses a week.

These announcements are the most important in the molecular farming space – although there have been others, such as by my long-time friend George Lomonossoff in the UK –  and the vaccine candidates are almost certainly going to be cheaper and quicker to make than conventionally manufactured subunit-based equivalents like the Coalition for Epidemic Preparedness Innovations (CEPI)-sponsored University of Queensland product announced recently. Indeed, a local “futurist” – Pieter Geldenhuys, interviewed by Moneyweb on 29th March – said, of the news that Medicago had developed a vaccine:

“Once one of the multitude of medical research teams have developed an effective vaccine for the strain prevalent in South Africa, it will take several months, or even years, before enough vaccines could be produced to fill the global need. This is where tobacco plants come in”

Geldenhuys’s advice for various governments around the world is clear. Keep your ear on the ground and start reaching out to companies like these. Once initial tests show success, consider building your own tobacco cultivation plants to ensure that you can reproduce the vaccine at speed.

A very recent article in the Wall Street Journal also soberly assesses the prospects of plant-made vaccines against SARS2 – with some help from some molecular farmers we may know B-)

Molecular Farming Manufacturing Possibilities in South Africa

Our group in the BRU, our recent spinout partners* Cape Bio Pharms, and a group at the SA Council for Scientific and Industrial Research (CSIR) are the three premier molecular farming research and development teams in South Africa. We have jointly made a host of candidate vaccines, virus-derived reagents for use in molecular biology labs and in diagnostics, and mAbs for use as reagents and potentially as therapeutics. Presently, Cape Bio Pharms and possibly the CSIR represent the only pilot-scale manufacturing facilities in South Africa for plant-made biologics, despite initiatives over years involving us and the CSIR and various government departments. A symposium in Franschhoek in the Western Cape Province in November 2017, hosted by the BRU and by iBio Inc of Bryan Texas, pitched a plan to assembled invited delegates for public/private partnership to construct a facility in this country to make pharmaceutical products using molecular farming technology. In announcing it, we said the following:

iBio’s plant growth facility, October 2018

“The conference brings together leaders from public agencies, academic institutions, parastatals, private companies, regulators and private capital to map out concrete steps to establish the plant-based manufacturing platform in South Africa. The Department of Science and Technology (DST) leads a broad science and technology innovation effort including of advanced health care products to create socio-economic opportunities.   The Technology Innovation Agency (TIA) is an active funder of human and animal health care initiatives in South Africa.     The Industrial Development Corporation (IDC) is a primary developer of manufacturing capacity and has important initiatives in biotechnology. Other participating agencies include the Council for Scientific and Industrial Research (CSIR), with its own molecular farming pipeline, and the Department of Trade and Industry (DTI).

AzarGen Biotechnologies is a private South African biotechnology company will be part of the private sector representation. AzarGen, primarily funded by the IDC, has worked with iBio for the last three years to develop biotherapeutics that include surfactin for infant respiratory distress syndrome and a biobetter rituximab monoclonal antibody for the treatment of non-Hodgkin’s lymphoma and certain autoimmune diseases. The BioVac Institute and Onderstepoort Biologicals, manufacturers of human and animal vaccine products respectively, will also present. ENSafrica will speak to Intellectual Asset Management and Cape Venture Partners will overview the private capital opportunities in South Africa. Technology Innovation Group, a US based consulting group, will talk about the structure of successful public/private partnerships.”

While the idea of a full-scale facility similar to iBio’s – costed at around USD30 million/R450 million – did not appeal to funders present, the idea of a cGMP-certified pilot manufacturing facility costing USD10 million – R150 million at the time – constructed using iBio’s expertise and assistance, found more favour. In fact, various entities promised to survey interested parties to establish the need and feasibility of internally funding it.

To the best of my knowledge, nothing along the lines of a survey has happened to date. Since then, and in the absence of any apparent interest from what were DST, DTI, IDC, TIA and others, iBio has gone on in 2019 to announce a partnership with Azargen in the area of rituximab biosimilar production, and as of a few days ago, as a contract manufacturing organisation, is offering their services in making COVID/SARS2 reagents at industrial scale in plants. Cape Bio Pharms has also established itself as a reagent manufacturer independently of any outside associations, with only local investment and a THRIP grant from Dept of Trade and Industry (DTI). I note that a previous proposal from some years ago involving the CSIR and Kentucky BioProcessing for establishment of an even cheaper pilot facility, also fell flat. For comparison, I will point out that the cost of just the revamping of Onderstepoort Biological Products’ (OBP, SA’s premier veterinary vaccine manufacturer) facility to be able to achieve cGMP certification is estimated to be ~R500 million.

SARS2/COVID Vaccines and Reagents for South Africa

Very early on in the present pandemic, Dr Mani Margolin of both the BRU and the Vaccine Research Group (VRG) of Prof Anna-Lise Williamson ordered a synthetic gene for a soluble version of the SARS-CoV-2 S protein, and has since successfully expressed the protein in both tissue cultured human cells, and in Nicotiana benthamiana plants via transient Agrobacterium-mediated expression. Both expression strategies leveraged technologies for which our research groups have either applied for or been granted patents, and established the very real possibilities of making both a DNA vaccine and a protein subunit vaccine against SARS2. He has gone on to insert the S protein gene into other vaccine vectors in the VRG.

Cape Bio Pharms (CBP)*, acting in parallel, ordered a gene for the “head” portion of the S protein – termed S1 – which they have also successfully expressed in N benthamiana, along with several variants of the protein, and they plan to collaborate with another new biotech company in South Africa to use it to produce mAbs for use as reagents, and potentially as therapeutics.

The CSIR is planning to leverage their established expertise in making mAbs to HIV and rabies in plants to produce a panel of mAbs to SARS2 for the same purposes.

These efforts have already resulted in ad hoc partnerships with other research groups and organisations, with S and S1 protein being supplied to others for use in establishing enzyme immunoassays and other diagnostic tests for serosurveillance and bedside testing, and other genes being shared with us and CBP for expression as reagents. I will note that the efforts that have resulted in the S-derived products are probably the fastest production at scales greater than a few micrograms in this country of any protein-based reagents, and probably the most quickly and cheaply scalable of any reagents. We are presently awaiting news of possible funding for molecular farming projects involving SARS2, albeit in a very rapidIy changing landscape where every day brings new developments – and where the future economic prospects of our country look dire, which may work against us.

Lessons From the Past

We have been here before, though. In 2006 our group received “Emergency Response” 1-year funding for H5N1 vaccine development from the Poliomyelitis Research Foundation (PRF) in SA – a then-handsome amount of R250 000 – which we then parlayed into another PRF 3-year grant, as well funding from the SA Medical Research Council (SAMRC). This quote from a profile published in Human Vaccines & Immunotherapeutics nicely sums up what we did:

As a result of a conference held in Cape Town in 2005, where a WHO influenza expert warned us “When the pandemic comes, you in the developing countries will be on your own”, we applied for extraordinary funding from the PRF in SA to explore the possibility of making a pandemic flu virus vaccine in South Africa. We chose the highly pathogenic avian influenza virus A H5N1 type haemagglutinin (H5 HA) as a target, and James Maclean was again instrumental in designing and successful early testing of plant-made soluble and membrane-bound forms. Further funding from the PRF and the SA MRC allowed proof of principle that we could in fact produce flu virus vaccine candidates in South Africa – both as [plant-made] subunit protein and as DNA vaccines.

In retrospect, while these projects were impossibly ambitious and not a little naïve, we and our co-workers received a crash course in both research vaccinology and the handling of big projects that has been crucial for all our subsequent work. We were also able to establish stable and well-qualified teams of people, with a nucleus of senior scientists who have been around us for up to 15 years. Another very important lesson was that we should patent our discoveries: in my case, this has led to me and my co-workers having the largest patent portfolio at our institution, and the largest molecular biotechnology-related portfolio in Africa – most of them to do with vaccines (14+ patent families). The development of a set of well-tried protocols around expression of novel antigens in a variety of systems has also been invaluable – especially when funding circumstances demanded that we change direction….

The potential importance of molecular farming for human health has been underlined recently with the apparently successful use of plant-produced MAbs (ZMapp) against Ebola virus disease in West Africa, and the proof of large-scale and rapid emergency-response production in plants of potentially pandemic influenza vaccines by Medicago Inc, among others [my emphasis] . We see our future role in exploiting niche opportunities for production of vaccine candidates and reagents for orphan or geographically-limited disease agents that do not attract Big Pharma attention – like CCHFV and RVFV – as well as for emerging animal diseases such as BTV and AHSV and BFDV, where rapid responses and small manufacturing runs may be needed [my emphasis].

Despite the fact that we ambitiously entitled our 2012 flu vaccine paper “Setting up a platform for plant-based influenza virus vaccine production in South Africa“, and our 2013 DNA vaccine paper as “An H5N1 influenza DNA vaccine for South Africa“, nothing happened. Nothing, despite the then Minister of Health Dr Aaron Motsoaledi saying during the influenza H1N1 2009 pandemic, that:

“South Africa has arrived at a situation where we have no option but to start developing our own vaccine capacity, not only for H1N1, but generally,” Motsoaledi told parliament.

“The disturbing feature about today’s world… has been expressed by the minister of health for Cambodia… who noted that the developed world, after producing the vaccine, may want to cover their own population first before thinking about the developing world,” Motsoaledi said.

It’s been nearly 11 years. Nothing has happened still. Despite distributing some 25 million doses of vaccines annually in South Africa, our only human vaccine firm – The Biovac Institute – still makes no virus vaccines. We have licenced our patented technology – for plant-made human papillomavirus vaccines and influenza virus vaccine – outside the country, for the lack of any interest locally.

This really should change. Maybe we have an opportunity now.

*= potential conflicts of interest due to partnerships.

Reviews on Molecular Farming

1: Dennis SJ, Meyers AE, Hitzeroth II, Rybicki EP. African Horse Sickness: A Review of Current Understanding and Vaccine Development. Viruses. 2019 Sep 11;11(9). pii: E844. doi: 10.3390/v11090844. Review. PubMed PMID: 31514299; PubMed Central PMCID: PMC6783979.

2: Rybicki EP. Plant molecular farming of virus-like nanoparticles as vaccines and reagents. Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2020 Mar;12(2):e1587. doi: 10.1002/wnan.1587. Epub 2019 Sep 5. Review. PubMed PMID: 31486296.

3: Chapman R, Rybicki EP. Use of a Novel Enhanced DNA Vaccine Vector for Preclinical Virus Vaccine Investigation. Vaccines (Basel). 2019 Jun 13;7(2). pii: E50. doi: 10.3390/vaccines7020050. Review. PubMed PMID: 31200559; PubMed Central  PMCID: PMC6632145.

4: Margolin E, Chapman R, Williamson AL, Rybicki EP, Meyers AE. Production of complex viral glycoproteins in plants as vaccine immunogens. Plant Biotechnol J.  2018 Jun 11. doi: 10.1111/pbi.12963. [Epub ahead of print] Review. PubMed PMID: 29890031; PubMed Central PMCID: PMC6097131.

5: Chabeda A, Yanez RJR, Lamprecht R, Meyers AE, Rybicki EP, Hitzeroth II. Therapeutic vaccines for high-risk HPV-associated diseases. Papillomavirus Res. 2018 Jun;5:46-58. doi: 10.1016/j.pvr.2017.12.006. Epub 2017 Dec 19. Review. PubMed PMID: 29277575; PubMed Central PMCID: PMC5887015.

6: Rybicki EP. Plant-made vaccines and reagents for the One Health initiative. Hum Vaccin Immunother. 2017 Dec 2;13(12):2912-2917. doi: 10.1080/21645515.2017.1356497. Epub 2017 Aug 28. Review. PubMed PMID: 28846485; PubMed Central PMCID: PMC5718809.

7: Williamson AL, Rybicki EP. Justification for the inclusion of Gag in HIV vaccine candidates. Expert Rev Vaccines. 2016 May;15(5):585-98. doi: 10.1586/14760584.2016.1129904. Epub 2015 Dec 28. Review. PubMed PMID: 26645951.

8: Rybicki EP. Plant-based vaccines against viruses. Virol J. 2014 Dec 3;11:205.  doi: 10.1186/s12985-014-0205-0. Review. PubMed PMID: 25465382; PubMed Central PMCID: PMC4264547.

10: Scotti N, Rybicki EP. Virus-like particles produced in plants as potential vaccines. Expert Rev Vaccines. 2013 Feb;12(2):211-24. doi: 10.1586/erv.12.147. Review. PubMed PMID: 23414411.

11: Thuenemann EC, Lenzi P, Love AJ, Taliansky M, Bécares M, Zuñiga S, Enjuanes L, Zahmanova GG, Minkov IN, Matić S, Noris E, Meyers A, Hattingh A, Rybicki EP, Kiselev OI, Ravin NV, Eldarov MA, Skryabin KG, Lomonossoff GP. The use of transient expression systems for the rapid production of virus-like particles in  plants. Curr Pharm Des. 2013;19(31):5564-73. Review. PubMed PMID: 23394559.

12: Rybicki EP, Hitzeroth II, Meyers A, Dus Santos MJ, Wigdorovitz A. Developing  country applications of molecular farming: case studies in South Africa and Argentina. Curr Pharm Des. 2013;19(31):5612-21. Review. PubMed PMID: 23394557.

14: Lotter-Stark HC, Rybicki EP, Chikwamba RK. Plant made anti-HIV microbicides–a field of opportunity. Biotechnol Adv. 2012 Nov-Dec;30(6):1614-26. doi: 10.1016/j.biotechadv.2012.06.002. Epub 2012 Jun 28. Review. PubMed PMID: 22750509.

15: Rybicki EP, Martin DP. Virus-derived ssDNA vectors for the expression of foreign proteins in plants. Curr Top Microbiol Immunol. 2014;375:19-45. doi: 10.1007/82_2011_185. Review. PubMed PMID: 22038412.

16: Rybicki EP, Chikwamba R, Koch M, Rhodes JI, Groenewald JH. Plant-made therapeutics: an emerging platform in South Africa. Biotechnol Adv. 2012 Mar-Apr;30(2):449-59. doi: 10.1016/j.biotechadv.2011.07.014. Epub 2011 Aug 3. Review. PubMed PMID: 21839824.

17: Rybicki EP, Williamson AL, Meyers A, Hitzeroth II. Vaccine farming in Cape Town. Hum Vaccin. 2011 Mar;7(3):339-48. Epub 2011 Mar 1. Review. PubMed PMID: 21358269.

18: Giorgi C, Franconi R, Rybicki EP. Human papillomavirus vaccines in plants. Expert Rev Vaccines. 2010 Aug;9(8):913-24. doi: 10.1586/erv.10.84. Review. PubMed PMID: 20673013.

19: Rybicki EP. Plant-made vaccines for humans and animals. Plant Biotechnol J. 2010 Jun;8(5):620-37. doi: 10.1111/j.1467-7652.2010.00507.x. Epub 2010 Mar 11. Review. PubMed PMID: 20233333.

20: Pereira R, Hitzeroth II, Rybicki EP. Insights into the role and function of L2, the minor capsid protein of papillomaviruses. Arch Virol. 2009;154(2):187-97. doi: 10.1007/s00705-009-0310-3. Epub 2009 Jan 25. Review. PubMed PMID: 19169853.

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Posted in biofarming, biotechnology | 28 Comments »

Papillomaviruses and human cancer

11 March, 2015

Human warts in all their forms – cutaneous, verrucous and genital growths and lesions – have been known since antiquity, and it was known since at least 1823 that at least some were infectious. Experiments done with human volunteers in the 1890s confirmed this, when it was shown that transplanting wart tissue resulted in typical disease.  As early as 1908, it was shown by a G Ciuffo that “verrucae volgare” – common warts – could be transmitted via a cell-free filtrate.  However, it was Richard E Shope who first showed that a papillomavirus was associated with animal tumours.  A useful review from 1931 on “Infectious oral papillomatosis of dogs” by DeMonbreun and the Ernest Goodpasture of egg culture fame covers the early history of the investigation of human disease as well as of animal papillomas very well, so we will not cover this further.

In light of later findings of the involvement of papillomaviruses, it was a prescient although premature observation by an Italian physician named Rigatoni-Stern in 1842 that cervical cancer appeared to be sexually transmitted, given that it occurred in married women, widows and prostitutes, but rarely in virgins and nuns.

Although papillomaviruses had been implicated as the first viruses known to cause a cancer in mammals as early as the 1930s, and the structurally very similar papovaviruses were similarly implicated in the late 1950s, it was only in 1972 that  Stefania Jabłońska proposed that a human papillomavirus (HPV; then called a papovavirus) was involved with the rare hereditary skin cancer called epidermodysplasia verruciformis.   

Meanwhile Harald zur Hausen had been investigating since 1974 the involvement of HPV in genital warts (condyloma accuminata) and squamous cell carcinomas, using DNA-based techniques such as hybridisation.  The rarely malignant condylomas had been shown to contain papillomavirus particles in some cases in 1968, with a better association in 1970; however, cross-hybridisation studies by zur Hausen’s group on DNA of these and common wart viruses showed no relationship despite their very similar morphologies. 

Virus particles from genital warts (6 &7) and a common skin wart (8). Reproduced from Brit. J. vener. Dis., JD Oriel and JD Almeida, 46, 37-42, 1970 with permission from BMJ Publishing Group Ltd.

Virus particles from genital warts (6 &7) and a common skin wart (8). Reproduced from Brit. J. vener. Dis., JD Oriel and JD Almeida, 46, 37-42, 1970 with permission from BMJ Publishing Group Ltd.

Zur Hausen speculated on the role of HPVs in squamous cell carcinomas in 1977; Gérard Orth and Jabłońska and colleagues went on to define the “…Risk of Malignant Conversion Associated with the Type of Human Papillomavirus Involved in Epidermodysplasia Verruciformis” in 1979.

Because this was the new era of cloning and sequencing of DNA, the zur Hausen group and others went on to isolate and characterise a number of new HPVs associated with genital cancers and other lesions in the early 1980s.  In particular, they showed that HPV types 16 and 18 could be found both as free virus in cervical cell sample biopsies and integrated into the cell genomes of cell lines derived from cervical cancers.  A major finding in 1987 was that the legendary HeLa cell line – derived from a malignant cervical tumour from a Henrietta Lacks in 1951 – contains multiple copies of the HPV-18 genome.  The first HPV genome sequence (of type 1b) was obtained in 1982; the first genital type (6b, from condylomas) in 1983, and the first high-risk cancer virus (type 16) in 1985.

Later work involving large international surveys showed by 1995 that 99.7% of cervical cancers contained DNA from so-called “high risk” HPVs, leading to the conclusion that these were the necessary cause of cervical cancer, and that around 70% of these cancers were caused by HPVs 16 and 18.  Since then, HPVs have been found in more than 80% of anal cancers, 70% of vulval and 40% of vaginal cancers, around half of all penile cancers, and in roughly 20% of head and neck cancers.  If 16% of cancers are due to infection, and HPVs cause or are implicated in 30% of these, then they are a significant cause of cancers worldwide.

Harald zur Hausen was awarded a half share of the 2008 Nobel Prize in Physiology or Medicine “for his discovery of human papilloma viruses [sic] causing cervical cancer”.  I blogged on this at the time, here.

Work on vaccines against papillomaviruses (PVs) started early, after demonstrations presumably in the 1930s that domestic rabbits inoculated with the cottontail rabbit PV (CRPV) could become immune to reinoculation after recovery, and in 1962 that a “…formalin-treated suspension of bovine papilloma tissue” provided protection against challenge, but was not therapeutic.  However, progress was stymied by the fact that it proved impossible to culture any of the PVs, and challenge material had to be made from infected animal tissue, even though it had been shown that isolated viral DNA was infectious.

This changed after the advent of molecular cloning, when whole viral genomes could be prepared in bacteria.  Model systems for use in PV vaccine research by 1986 included cattle and bovine PVs, rabbits and CRPV and rabbit oral PV, and dogs and canine oral PV.  It had also been demonstrated that the L1 major structural protein of type 1 BPV produced in recombinant bacteria was protective against viral challenge in calves.  Jarrett and colleagues demonstrated, in 1991 and 1993 respectively, that they had achieved prophylactic and therapeutic immunisation against cutaneous (ie: skin; caused by BPV-2) and then mucosal (respiratory tract; BPV-4) bovine PVs, using E coli-produced proteins.  L1 and L2 proteins were protective against BPV-2, while L2 was protective against BPV-4 infection.  They suggested BPV-4 was a good model for HPV-16 given its mucosal tropism.

By the early 1990s several groups had demonstrated that it was possible to make PV virus-like particles (VLPs) by expression in eukaryotic systems such as yeast or animal cells of the L1 major virion protein either alone, or together with the minor protein L2.  In 1991 Ian Frazer’s group showed that expression of HPV-16 L1 and L2 together but not separately in animal cells via recombinant vaccinia virus, resulted in 40 nm particles resembling the virion being made.  In 1992 John Schiller’s lab showed VLP formation by L1 alone, with both BPV-1 and HPV-16 L1 genes expressed in insect cells via a baculovirus vector. In 1993 came the demonstration that expression of the plantar wart-causing HPV-1 L1 gene alone and L1 and L2 genes together in animal cells via vaccinia virus, as well as of the genital wart-causing HPV-11 L1 expressed in insect cells, resulted in VLP formation.  By 1995, it had been shown that immunisation of rabbits with CRPV L1-only or L1+L2 VLPs, and of dogs with canine oral PV L1 VLPs, protected completely against viral challenge.

hpv vlps

This groundwork made it possible for Merck and GlaxoSmithKline to develop and to push through to human trial and licensure, two independent VLP-based vaccines.  Merck’s vaccine – Gardasil – is quadrivalent, consisting of a mixture of VLPs made in recombinant yeasts from expression of L1 genes of HPV types 6 and 11, to protect against genital warts, and types 16 and 18, for cervical lesions and cancer.  GSK’s offering – Cervarix – is a bivalent HPV-16 and -18 vaccine only, consisting of VLPs made via recombinant baculoviruses in insect cell culture.  These are only the second anti-cancer vaccines on offer, and have gone on to blockbuster status within months of their release: Gardasil was licenced in June 2006, and Cervarix in October 2009.

Both appear to protect very well against infection with the types specified, but not to affect established infections.  Their long-term efficacy against cervical cancer is still to be established, although Gardasil has certainly lessened the incidence of genital warts in Australia post introduction in 2007.  There is now also a VLP-based vaccine for canine oral PV.

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Posted in biotechnology, Evolution, General Virology, history, HPV, Vaccines: General, Viruses | 1 Comment »

A Short History of the Discovery of Viruses

6 March, 2015

Now much updated, streamlined, added to and otherwise tarted up!  This is the Web version of an eBook, which you can now get here:

A Short History of the Discovery of Viruses – Edward Rybicki

Slide1

See also here for a “pocket reference version” of the discovery of viruses

Part 1: Filters and Discovery

Part 2: The Ultracentrifuge, Eggs and Flu

Part 3: Phages, Cell Culture and Polio

Part 4: RNA Genomes and Modern Virology

Sidebar 1: The Discovery of Filoviruses

Sidebar 2: Papillomaviruses and Human Cancer

Sidebar 3: Epstein-Barr Virus and Hepatitis B Virus

Sidebar 4: Human Retroviruses and Cancer

Sidebar 5: Maize Streak Virus: The Early History

Sidebar 6: Rinderpest and Its Eradication

Sidebar 7: Viruses and human cancer: the molecular age

Copyright Edward P Rybicki and Russell Kightley, February and March 2015, except where otherwise noted.

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Posted in General Virology, history, HIV, Influenza viruses, phages, Vaccines: General | 16 Comments »

Emergency response vaccines for H5N1 influenza in South Africa

1 November, 2013

Our group has been working for some time now – since 2006, in fact – on investigating the feasibility of providing South (and southern) Africa with emergency response pandemic influenza vaccines.  The research was initiated after the Virology Africa 2005 conference that Anna-Lise Williamson and I organised in the Cape Town Waterfront in November of that year – when a senior WHO official warned us in his talk that “…if a pandemic hits, you are on your own: no-one will give you any vaccine”.

A group of us sat down afterwards, and discussed the feasibility of looking at emergency response vaccine(s), given that we had no capability in the whole of Africa to make flu vaccines.  Anna-Lise and I put together a proposal, with the highly pathogenic avian H5N1 influenza A as a target, which was funded on a once-off one-year basis by the Poliomyelitis Research Foundation (PRF) here in SA for 2006 – and then again by the PRF as a three-year Major Impact Project  (MIP) from 2008-2010, and subsequently to a lower level by both the PRF and the Medical Research Council of SA.  What made it all the more impressive for a South African project was that we had proposed expressing a protein-based vaccine in plants – quite a revolutionary prospect at the time, but something that followed on from the highly successful production of Human papillomavirus virus-like particles by transient expression in Nicotiana benthamiana by  James Maclean, working as a postdoc in our lab at the time.

However, some of the most important work was done early: James was very quick to get the haemagglutinin (HA) gene for the A/Vietnam/1194/2004 strain of H5N1 synthesised by GeneArt in Germany, and cloned into the same Agrobacterium tumefaciens plant expression vectors from Professor Rainer Fischer’s lab in Aachen, Germany, that had been used for HPV.  His initial work showed that large amounts of HA protein could be produced, both as soluble protein which lacked a membrane localisation domain, and as the membrane-bound form.  This work formed the basis for a patent application on the transient expression of H5 HA that has now been granted.

Subsequently, when the PRF MIP started, we employed Dr Elizabeth (Liezl) Mortimer and Ms Sandiswa Mbewana to further the work: with collaborators from the National Institute for Communicable Diseases (NICD) in Johannesburg and State Veterinary Services in Stellenbosch, this investigated transient and transgenic expression of soluble and membrane-bound forms and their immunogenicity, as well as a DNA vaccine consisting of the HA genes cloned into Tomas Hanke’s pTH vector.

The protein expression work was published in 2012, as well as being featured here in ViroBlogy at the time.

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What we had managed to show was that we could get excellent production of the H5 HA in both soluble and bound forms, and that especially the membrane-associated form of the protein was highly immunogenic, and elicited antibodies in experimental animals that were appropriately neutralising, indicating its suitability as a vaccine candidate.

Now this all happened despite our running out of money AND Liezl leaving to have a baby…and then we managed to get another paper out of the work, this time on the DNA vaccine side of things.

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We pitched this at the South African Journal of Science as a vindication of the faith in us by exclusively South African funding agencies – and managed to get the cover of the issue in which it appears, thanks to the truly excellent artwork of Russell Kightley from Canberra, Australia.  Front AND back covers, as it happens…!

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And this all made Sandiswa Mbewana, who is now a PhD student on another project, very happy:

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This all came in excellent time to mark the establishment in the Department of Molecular and Cell Biology at the University of Cape Town, of a new URC Research Unit: namely, the Biopharming Research Unit (BRU).

BRU

Watch this space…B-)

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Plant-Based Antibodies, Vaccines and Biologics 5, Part 5

3 September, 2013

Session 6:Vaccines II

This was SUPPOSED to open with a report from Medicago Inc, on ‘Developing plant-made influenza vaccines: From discovery to commercial scale production’  – but didn’t, because they were all shaken up (in a good way) by having been effectively bought by Mitsubishi Tanabe Pharma Corporation, and no-one came.

This is a success story in its own right, however, as their recent and highly successful activities in the areas of making influenza vaccines and human rotavirus VLP-based vaccines in plants marked them out as a target for acquisition by Big(gish) Pharma – for which we commend them.

It is sad, however, that their only presence at the conference was on the back of my windbreaker B-)

Konstantin Musiychuk (Fraunhofer USA) was the first up, then, speaking on ‘Preclinical evaluation of VLP-based malaria transmission blocking vaccine’.  He described how there are 3 types of intervention that may work with malaria: these are at the pre-erythrocytic, blood stage, and transmission blocking stages of infection.  Antibodies to Pfs48/45, Pfs230 proteins block the fertility of or destroy the macrogamete.  Pfs25 and 28 Abs block the ookinete to oocyst developmental phase; all potentially block transmission.  Accordingly, they expressed these as fusions with the alfalfa mosaic virus (AMV) CP with mutation(s) to prevent glycosylation.  The Pfs25 protein was the best candidate; they cloned a mutated version (glyc-), fused at the N-terminus to AMV CP, and expressed via their TMV-based “launch vector” after vacuum infiltration.  He noted that the fusions have full-length and proteolysed products – which is needed for VLP formation as native CP is needed to avoid steric hindrance in assembly.  They obtained nice particles as shown by EM, showing surface decoration.  Dynamic light scattering [Ed: must get me one of those…] results show a nice tight range of 17nm particles.

They used the products with/out Alhydrogel as adjuvant, IM in mice: they got good titres maintained >170 days, with  2x inoculation.  They diluted test sera with naive human serum and used this to membrane-feed mosquitoes, then after 1 week dissected them and assayed for parasites: oocyte counts in mid-gut reflected efficient blocking of acquisition.  The adjuvant+ doses worked well down to 0.1 ug (100%).  Single doses of 1, 5 or 25 worked 100% as well.  After 6 months, 5 and 25 ug doses still gave 90%+ blocking.

They made GMP lots, very pure:  2 doses at 0 and 21 days resulted in complete blocking down to 0.3 ug, with >99% blocking after 40+ days.  Tox studies were fine, although the  Alhydrogel apparently causes some side effects.   Scaleup from 1-50 kg showed no changes in the Ag.  The Phase 1 trial is expected in Q3 2013.

This was most impressive: it is to be hoped that the promise is maintained!

Yoseph Shaaltiel (Protalix Biotherapeutics, Israel) spoke on Protalix’s new product: this was alpha galactosidase-A, for the treatment of Fabry disease.  This is an X-linked lysosomal storage disease that results in massive storage of glycolipid Gb3, in cells, in the vascular system and elswhere, which impairs the tissue of the heart and affects kidney and other organ function.  There were worse consequences than with Gaucher disease, while it was less obvious.  The current therapy was seen as being bad, and patients had reduced life expectancy.  There were 2 therapeutic enzymes on the market: these were Agalsidase Alfa and Beta; these were very inefficient and expensive, so cost benefit was very limited.  1/2 life in blood was normally just a few minutes, and the proteins were very immunogenic.

Protalix aimed at making a biobetter: this was made in tobacco cells cultured in bags (they used Icon vectors, so could not work in their favoured carrot), by cocultivation with Agrobacterium and then killing the bacteria.  The protein subunits were PEGylated to reduce immunogenicity and x-linked using bis-NHS-PEG.  This gave improved stability, longer circulatory 1/2 life, enhanced activity in target organs with similar to improved kinetics, so lower dosing and longer intervals between doses were possible.  Yields were good too, and they could make the enzyme very pure.  The product had the same kinetics as the commercial products with better activity over a wide pH range.

As far as glycosylation was concerned, the commercial product had very complex glycosylation, while the plant-made product’s profile was very consistent and simple.  It had an enhanced circulatory 1/2 life, of 581 vs 13 min, and also had higher activity in target cells – heart, kidney – over time.  Yoseph noted that the  patents on the enzyme(s) were limited to CHO cell production, meaning they had a useful window to exploit.

A comment from Jim Carrick was that the FDA was not interested in PEGylated products, as this could lead to vacuolation of kidneys in the long term.  Yoseph said their product was not the same, as normally PEGylation added 20-40 kDa, whereas theirs was a much shorter x-linker.  Their product was, moreover, already in clinics, as the  FDA had said they should move straight to patients rather than testing it in healthy people.

Lydia Meador (Arizona State University) reported on their lab’s HIV vaccine candidate, made in plants and also vectored by NYVAC-KC delB19 poxvirus.  They had previously shown that a CTB-HIV membrane proximal region (MPR) fusion vaccine resulted in Ab that stops transcytosis of HIV by Ab; she noted that live vectors enhance T-cell responses compared to subunit vaccines, so a combination would be a good idea.

Accordingly, they had cleverly produced whole HIV Gag and a deconstructed gp41 – stable Gag transgenics, and transiently-produced dgp41 – in the same plants, to make 100nm VLPs.  While VLPs are highly immunogenic alone, they wanted to prime with the NYVAC and boost with plant-made antigen.  They obtained good p24 Ab responses with NYVAC and the VLP boost; gp41 less so.  In terms of mucosal immunity, they saw the IgA response against gp41 was significantly higher in the NYVAC+VLP combination, as were CD8+ T-cells.  She noted that the anti-NYVAC titre was high after 3x doses.  In response to my question, she did not know if the NYVAC vaccine made VLPs in mice – which it may not do, even if it works in plants, due to different protein requirements for budding in mouse vs plant cells.

Daniel Tusé (Intrucept Biomedicine, Kentucky) – a company founded with Kenneth Palmer – spoke on ‘Safety and efficacy of plant-produced Griffithsin for antiviral indications’.  He noted that while griffithsin was an excellent anti-HIV microbicide, it was also a reasonably broad-spectrum antiviral lectin, as it was effective against the recently-emerged MERS CoV and  influenza viruses.

The protein was hard to make from seaweed, and E coli was useless for production; however, they got g/kg in tobacco via conventional rTMV vectors, and now even better with Icon and Nomad vectors.  KBP had manufactured it to near-GMP production standards, again at g/kg yields, with product recovery at 30% from leaves and 50% from leaves + stems, to a final purity of 99.8%.  The potency was the same as the alga-derived product, and they had 100s of gm of product.

As griffithsin binds HIV with very high affinity, its primary use would be as a topical microbicide, to prevent transmission of HIV and HSV; to prevent coronavirus infections, and to act on chronic virus infections.  The protein is not mitogenic on PBMC and does not activate T cells; it does not produce inflammatory cytokines in human PBMC, unlike cyanovirin, which had a much worse proinflammatory profile.  The epithelial toxicity was also very low, which was in contrast to some well-publicised agents which had disastrously resulted in increases of HIV acquisition in women using them.

A carbopol-based gel was found to have the best drug-release kinetics, so was adopted for formulating the product for use.  This protects mice against genital herpes: herpes has 2x the risk of infection per exposure compared to HIV infection.  The gel has broad specific activity against coronaviruses too, to a wide spectrum of viruses from human, cow, chicken and pig.  It could protect mice against SARS CoV, if given intranasally at 2 doses/day.

The protein also has uses in prevention of infection in the organ transplant area, eg against hepatitis C virus (HCV): it prevents infection of Huh-7 cells by cell-culture derived HCV, and partially protects hepatocytes from viral spread in vivo.  If injected in animals it persists, and maintains an anti-HIV activity.  It is immunogenic, but only weakly so, and Ab to it don’t neutralize its effects.  Their lab was using rational design to take out T-cell epitopes without affecting antiviral activity.

Daniel stressed that this is a new drug, which can be preferentially be made in plants at high yield, with very low cost of goods; that it was effective and safe.

Hugh Haydon (KBP) mentioned that the cost of goods was “pennies/dose”.

Session 8:

This was an interactive discussion session, addressing the topic ‘Commercialisation of molecular pharming products – objectives and targets for the next 5 years’.

The panel: from left - Hugh Haydon, Kevin Whaley, John Butler, Scott Deeter, Einat Brill

The panel: from left – Hugh Haydon, Kevin Whaley, John Butler, Scott Deeter, Einat Brill

Hugh Haydon of Kentucky BioProcessing (KBP), , speaking on behalf of the new MAPP, KBP and Icon collaboration, addressed product selection.  He noted that MAPP was responsible for product development, Icon for technology development and purification, and KBP for large-scale manufacture.  They had spun out Solmab as a collaborative vehicle for production of MAbs for infectious disease therapy.

He described their product selection rationale: this was based on

  • proof of concept data
  • platform suitability
  • capacity for dual use of product
  • availability of capital
  • speed of the regulatory process
  • regulatory success rate
  • scalability of existing infrastructure

Accordingly, they had selected a “biobetter” of Synagis, and an Ebola MAb cocktail.  The Synagis equivalent was better due platform parameters, known clinical parameters, the fact there were established markets which can grow, government and NGO humanitarian interest, and potential adaptation to other viruses.  For Ebola, they had a 3 MAb cocktail that was known to work, strong government interest (for a stockpile), a more rapid regulatory pathway, and a tropical disease voucher from the FDA.  He pointed out that these products won’t make blockbuster status, but are appropriate for small companies like theirs.

Kevin Whaley (MAPP) spoke on how we needed therapeutics that were multipurpose (disease, indication) as well as multi-vaccines.  The attributes of the new biologics were multi-use, speed of production, scale of production, and cost advantage – especially for global health products costing <$US10/g, at scales of >10K kgs, with increased efficacy (pathology, cancer), increased acceptability and access.  He noted that all modern paediatric vaccines are multi – this saves visits to clinics, especially in developing countries.

Scott Deeter (InVitria) noted that the biologics market was edging up to being worth $US125 billion – and reckons progress with plant-produced products is excellent.

John Butler (Bayer) thinks we are still looking for suitable products!  He was of the opinion that initial targets were too difficult (eg NHL – and flu??!), and that improved product characteristics must benefit from being plant-made.  He was adamant that PMP must not compete on price with other platforms – because there was no such thing as a bottleneck in fermentation capacity world-wide, and established industry could just cut prices if they wanted to.  He spoke of real and perceived hurdles:

  • regulatory pathway isn’t a hurdle
  • plant vs human glycosylation is not either, as plant-specific glycans were not more immunogenic than human

Real risks were that:

  • there were well-established alternatives
  • the plant-made product industry was overstretched in terms of resources

Einat Brill (Protalix) addressed their future strategy:

  • new biologics for orphan indications (clinical trials were smaller, one needed only several 10s kg a year for an entire disease cohort)
  • recombinant vaccines
  • hard to express proteins that were best expressed in plants

ApApproved biologics:

  • Biobetters of commercial products
  • They would continue to establish PMP regulatory environment as a viable route for biologic drugs development
  • Biobetter efficacy: longer circulatory half life for favourable clinical outcome
  • regimen frequency: longer treatment intervals due to increased drug stability, with lower dosing
  • Changing administration route (eg: oral vs injectable): helps to improve patient compliance

This was an excellent session, if only to hear how people who have been involved in getting PMPs to the market viewed the prospects for the industry – and it appeared favourable, despite John Butler’s caveats.

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Moratorium on using live rinderpest virus lifted for approved research

30 July, 2013

See on Scoop.it – Virology News

Benefits of future research should be carefully balanced against potential risks

Paris, 10 July 2013 – A moratorium on using live rinderpest virus for approved research has been lifted by the Food and Agriculture Organization of the United Nations and the World Organisation for Animal Health (OIE).

The moratorium followed the adoption of a Resolution in May 2011 by all OIE Member Countries that urged members to forbid the manipulation of rinderpest virus containing material unless approved by the Veterinary Authority and by FAO and OIE.

The two organizations have now put in place strict criteria and procedures to follow in order to obtain official approval for any research proposals using rinderpest virus and rinderpest virus-containing materials. One of the most crucial requirements is that the research should have significant potential to improve food security by reducing the risk of a reoccurrence of the disease. This procedure replaces an earlier complete ban on handling the virus.

Rinderpest was formally declared eradicated in 2011, but stocks of rinderpest virus continue to exist in laboratories. In June 2012, a moratorium on handling the virus was imposed after an FAO-OIE survey found that the virus continues to be held in more than 40 laboratories worldwide, in some cases under inadequate levels of biosecurity and biosafety.

When rinderpest was officially eradicated, FAO and OIE member countries committed themselves to forbid the manipulation of rinderpest virus-containing material unless approved by the national veterinary authority as well as by FAO and OIE.

Paramyxovirus EM courtesy of Linda Stannard

Thanks to Len Bracher for alerting me to this.

Ed Rybicki‘s insight:

This is an interesting sequel to the eradication of wild rinderpest virus, which I have covered in some detail here on ViroBlogy: see here (https://rybicki.wordpress.com/2010/11/05/rinderpest-gone-but-not-forgotten-yet/) and here (https://rybicki.wordpress.com/2011/08/03/deliberate-extinction-now-for-number-3/).

The article covers an interesting prospect: that it may be possible to use attenuated, safe vaccines against the related peste des petits ruminants virus (PPRV) not only to protect against any resurgence of rinderpest, but also to eradicate this rather nasty virus.

Which is, apparently, spreading at rather an alarming rate, and is an obstacle to small ruminant production (http://www.fao.org/ag/againfo/resources/documents/AH/PPR_flyer.pdf).

So maybe this is “Now for Number 4!” time.

See on www.oie.int

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Plant-Based Vaccines, Antibodies and Biologics 5: Part 1

27 June, 2013

Plant-Based Vaccines, Antibodies and Biologics: the 5th Conference

Verona, Italy, June 2013

The return of this biennial meeting to Verona – the third time it has been held here – was a welcome change; while the previous meeting in Porto in 2011 may have been good, the city was nothing like as pleasant a place to relax.  My group is now familiar enough with Verona that we know just where to go to get pasta by the riverside – or, on this occasion, “colt loin with braised onion and potatoes” and “stewed horse with red wine”.  Which seem more palatable, somehow, as “Costata di puledro con cipolle brasate e patate” and “Stracotto di cavallo speziata” respectively, but were enjoyed anyway.

The conference kicked off with an opening plenary session, chaired by the Local Organizing Chair, Mario Pezzotti, of the University of Verona.  The headline act was a talk on taliglucerase alfa – aka glucocerebrocidase, a Gaucher Disease therapeutic  –  by Einat Almon of Protalix Therapeutics from Carmiel, Israel.  I featured the product here last year, after an earlier feature here; suffice it to say that it has soared since FDA approval, and now Protalix is pushing hard with new plant-made products to follow it up.  While they use carrot cells for taliglucerase alfa, apparently they are using suspension-cultured tobacco cells for other products – and are using an easily-scalable disposable 800 litre plastic bag system, with air-driven mixing of cells suspended in very simple, completely mammal-derived product free media.  Hundreds of patients had been treated with the drug for up to 5 years with no ill effects, and the possibility of switching therapies from mammalian cell-made products to the plant cell-made had been successfully demonstrated.

Scott Deeter of Ventria Biosciences (Ft Collins, USA) spoke next, on “Commercializing plant-based therapeutics and bioreagents”.  His company has possibly the most pragmatic attitude to the production and sale of these substances that I have yet met, and he struck a number of chords with our thinking on the subject – which of course, post-dates theirs!  Ventria use self-pollinating transgenic cereals for production of seed containing the protein of interest, and rice in particular, for safety reasons – and because the processing of the seeds is very well understood, and the purification processes and schedules are common to many food products and so do not require new technology.  He reckoned that a company starting out in the business needed an approved product in order to give customers confidence – but should also engage in contract services and contract manufacture of client-driven products in order to avoid being a one-product shop.  To this end, they had received APHIS Biological Quality Manufacturing Systems (BQMS) certification (similar to ISO9001), with the help of the US Biotechnology Regulatory Services.

Their therapeutic products included diarrhoea, ulcerative colitis and osteoporosis therapeutics which were already in phase II clinical trial.  Scott noted that in particular, recombinant lactoferrin was a novel product, which could only feasibly be produced in the volumes and at the price required for effective therapy, by recombinant plant-based production systems.  It also filled a high unmet need as a therapy for antibiotic-associated diarrhoea in the US, with +/-3 million patients at risk annually who presently cost service providers over $1500 each for treatment.

A third commercialization option was bioreagents and industrial enzymes, which they marketed via a vehicle called InVitria: they had a number of products already in the market, which Scott claimed gave confidence to the market and to partners, while building capacity to make therapeutics.  Something that was particularly attractive to our prospects was that a collection or pool of small volume products – say $5-10 million each – gave a respectable portfolio.  He noted that Sigma Aldrich and Merck were already marketing their human serum albumin, which competed effectively with serum- and yeast-derived products.

George Lomonossoff from the John Innes Centre in Norwich, UK, spoke next on “Transient expression for the rapid production of virus-like particles in plants” – a subject close to our hearts, seeing as we have for the last five years been associated with George and partners in the Framework 7-funded PlaProVa consortium.  He mentioned as an object example the recent success in both production and an efficacy trial of complete Bluetongue virus (BTV) serotype 8 VLPs, made in Nicotiana benthamiana via transient expression using their proprietary Cowpea mosaic virus (CPMV) RNA2-derived pEAQ vector: this was published recently in Plant Biotechnology Journal.

Another very useful technology was the use of CPMV capsids as engineered nanoparticles: one can make empty VLPs of CPMV at high yield by co-expressing the coat protein (CP) precursor VP60 and the viral 24K protease: the particles are structurally very similar to virions in having a 0.85 nm pore at 5-fold rotational axes of symmetry, meaning they can be loaded with (for example) Co ions.  It is also possible to fuse targeting sequences – such as the familiar RGD loop – into the surface loops of the CPMV CPs, and to modify the inner surface too.  One application would be to engineer Cys residues exposed on the inside, which could bind Fe2+ ions: this would result in particles which could be targeted to cancer cells by specific sequences, then heated using magnetic fields.

John Butler of Bayer Innovation GmbH (Leverkusen, Germany) closed out the session with an account of lessons learned from the development of the plant-derived non-Hodgkins lymphoma (NHL) vaccine, that they had acquired with Icon Genetics, who in turn had inherited it from the sadly defunct Large Scale Biology Corp.  It was rather depressing to hear that Bayer had dumped the vaccine, despite the developers having reached their targets in turning 43 of 45 tumour samples into lifetime individualized supplies of vaccine within12 weeks, and despite the phase I trial being as successful as could be hoped.  To this end, the vaccines had been well tolerated and were immunogenic; of the patients who reacted immunologically, all but one were still tumour-free presently.

He felt that the problem was that NHL trials were too long and therefore too expensive as it was a slow-progressing disease; that a different clinical approach was needed, and that using the vaccines as a first-line therapy instead of only after the 2nd or 3rd relapse would be a much better idea.  The main lesson learned was that proving the technology would be far better done with a therapeutic vaccine for a fast-acting cancer, which would allow 1-2 year clinical trials with overall survival as an endpoint.

(more coming)

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HPV vaccines for South Africa: coming to a school near you!

19 May, 2013

From The Independent Online:

HPV and cervical cancer: courtesy Russell Kightley Media

HPV and cervical cancer: courtesy Russell Kightley Media

“Cape Town – Government will start administering cervical cancer vaccines in schools from February next year, Health Minister Aaron Motsoaledi has announced.

Speaking during the health budget vote debate in the National Assembly on Wednesday, Motsoaledi said government hoped to negotiate lower prices for the vaccine, which treats the Human Papilloma Virus (HPV) – the major cause of cervical cancer among women.

Quoting experts, he said cervical cancer affected 6000 South African women a year, 80 percent of them black. More than half the women affected died of the disease.

While the HPV vaccine presented an opportunity to prevent women from contracting cancer, there were still obstacles to overcome.”

This is a really, really big deal for South Africans – and pity is, the vaccine will not be given to boys, or universally to girls.

Seriously: all the science says that giving it to boys as well limits spread of the viruses far better; not making it universally available will mean all sorts of recriminations around unequal access (read: to less privileged kids ONLY as part of the government programme at first).

But a big step in the right direction!

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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!

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ViroBlogy: 2012 in review

1 February, 2013

So: thank you, anyone who clicked in, and regular visitors.  You make it worthwhile!!

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 33,000 views in 2012. If each view were a film, this blog would power 8 Film Festivals

Click here to see the complete report.

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Posted in biofarming, biotechnology, Ebola, Evolution, General, General Virology, HIV, Influenza viruses, Marine Viruses, plant viruses, Vaccines: General, Viruses | Leave a Comment »

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