ISIS Press Release 05/01/09
Major uncertainties over efficacy and safety for costly vaccines that only benefit the drug giants for sure
Prof. Joe Cummins and Dr. Mae-Wan Ho
Two years ago we reported on recombinant vaccines against the human papilloma virus (HPV) infection and cervical cancer [1] (Recombinant Cervical Cancer Vaccines, SiS 29). Clinical trials had been completed on two vaccine formulations, and these are being commercially released worldwide in government sponsored vaccination programmes that target women and girls (and even boys) as young as 9 years of age in a bid to prevent cervical and anogenital cancers [2]. This has aroused a great deal of controversy, which calls for a fuller discussion.
Human papillomavirus
According to the US government’s National Cancer Institute [3], human papillomaviruses (HPVs) are a group of more than 100 viruses. Certain types cause warts or papillomas that are benign. The HPVs that cause the common warts on hands and feet are different from those that cause growth in the throat or genetial area. Some types are associated with cancer, and are called “high risk” HPVs.
Of the more than 100 types of HPVs, over 30 can be passed through sexual contact. Most HPV infections occur without any symptoms and go away without treatment over the course of a few years. However, HPV infection sometimes persists for many years, with or without causing detectable cell abnormalities.
Infection with certain “high risk” types of HPV is the major cause of cervical cancer. Almost all women will have HPV infections at some time in their lives but very few will develop cervical cancer, as the immune system of most women will usually suppress or eliminate HPVs. Only HPV infections that persist can lead to cervical cancer. An estimated 11000 cases of this kind of cancer is diagnosed in 2007 in the United States, with less than 4 000 deaths; so cervical cancer is not among the major cancers in the US. Worldwide, cervical cancer strikes nearly half a million women each year, claiming more than a quarter of a million lives.
High risk” HPV types 16 and 18 are implicated in 70 percent of cervical cancers and are hence selected for vaccine targets.
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ISIS Press Release 07/01/09
Dangers of HPV Vaccine Production in Plants, Microbes, and Viruses
Widespread releases of hazardous transgenes and vaccines have the potential to create viruses more deadly than the ones the vaccines protect against
Prof. Joe Cummins and Dr. Mae-Wan Ho
Human papilloma virus (HPV) vaccines are already commercialised and promoted worldwide in a bid to protect young girls and women from cervical cancer [1, 2] (Recombinant Cervical Cancer Vaccines, SiS 29; The HPV Vaccine Controversy, SiS 41), while there is still major uncertainty over their efficacy and safety, especially in the long term. One obstacle to the adoption of the vaccines by developing countries is that the two available are very costly. There appears to have been a rush to create cheap oral HPV vaccines in transgenic plants, microbes and viruses that do not require refrigeration and can be distributed relatively inexpensively, but would involve widespread releases of hazardous transgenes and products into the open environment. Some of these are near commercialization, and regulators must be warned against the approval of such production methods unless and until strict containment and safeguards are put in place.
HPV vaccines in crop plants
The main concern over the vaccines produced in crop plants is that transgenes from tests sites or production farms can readily spread by pollen or by mechanical dispersal of seeds. Debris from transgenic crops can also spread transgenes and vaccine proteins through contaminating surface and groundwater. Debris in the form of dust in the air can impact on the respiratory mucosa directly, with the potential of triggering acute and delayed immune reactions in humans and animals exposed. HPV vaccines have already been associated with various adverse acute immune reactions some of which resulted in death [2]. People subject to persistent exposure to the crop vaccine are likely to develop oral tolerance rendering them susceptible to virus infection [3] (Pharm Crops for Vaccines and Therapeutic Antibodies, SiS 24)..
There have been reports since 2006 that HPV virus and L1 proteins were produced in plants including transgenic potato, tobacco and a wild tobacco N. benthamiana [4]. HPV L1 virus-like particles were expressed in transgenic potatoes and these particles were found to immunize animals fed the potatoes. The gene for the particle protein L1 had been optimized for activity in potato by codon alterations. The full length message had a C-terminal signal sequence for nuclear localization of the protein and production of the L1 protein is enhanced by removal of the signal sequence for nuclear localization. The oral immunization using transgenic potato had to be enhanced by ingesting LI protein produced from insect cell (baculovirus) cultures.[5]. Comparing the production of HPV19 L1 in cytoplasm or chloroplast of Nicotiana benthamiana showed that the vaccine was produced most effectively in the chloroplasts. Adjustments in codon preferences showed that the human codon preference was most effective in enhancing production of the vaccine. The optimally engineered gene configuration produced up to 11 percent of the plant’s soluble protein as L1 vaccine protein [6]. The HPV 16 L1 protein produced in N. benthamiana proved very immunogenic following injection in mice [7]. Another N. benthamiana chloroplast transformation produced up to 1.5 percent total leaf protein as HPV L1 whose half life in the leaf was at least 8 hours [8].
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http://www.i-sis.org.uk/HPV_Vaccine_Production_Plants.php
http://freepage.twoday.net/search?q=HPV
