Science in Society Archive


Our fields are being turned into pharmaceutical and industrial factories that poison our food supply and entire life support system. Our governments have been warned and should be held liable for all damages along with the companies involved. Dr. Mae-Wan Ho reports.

We have repeatedly warned against using food crops to produce gene drugs and industrial chemicals since 1998 [1-3]. The inevitable contamination of our food supply has now come to light. But the more insidious pollution of our soil, water and air has yet to be assessed [3]. Poisons can seep through the plant roots and dissolve in ground water. Pollen carrying the offending drugs and chemicals could be inhaled. Wild and domestic animals of all kinds are likely to feed on the crops.

On November 11, the US government ordered the biotech company, ProdiGene, to destroy 500,000 bushels of soybeans contaminated with GM maize, engineered to produce a drug not approved for human consumption [4]. The US Department of Agriculture (USDA) refused to give details on the protein involved because it is deemed ‘confidentual business information’.

It could be one of the following [5]: the HIV glycoprotein gp120, a blood-clotting agent (aprotinin), a digestive enzyme (trypsin), an industrial adhesive (a fungal enzyme, laccase), vaccines for hepatitis B, vaccine for a pig disease, transmissible gastroenteritis.

USDA records show that ProdiGene has received 85 test permits for experimental open-air trials of pharm crops and chemical crops in at least 96 locations.

The ‘edible’ AIDS vaccine with the HIV glycoprotein gp120 gene [6] has been condemned as dangerous by a number of AIDS virologists [7-9] because the gp120 gene and gene product can undermine our immune system and generate new viruses and bacteria that cause diseases.

A day later, the US government disclosed that ProdiGene did the same thing in Iowa back in September. The USDA ordered 155 acres of nearby corn to be incinerated for fear of contamination [10,11].

This is just be the tip of the iceberg. The true extent of the contamination remains unknown owing to the extreme secrecy surrounding more than 300 field trials of such crops across the country since 1991. Still others sites are in Canada [3]. The chemicals these plants produce include vaccines, growth hormones, clotting agents, industrial enzymes, human antibodies, contraceptives, immune suppressive cytokines and abortion-inducing drugs.

The majority of engineered biopharmaceuticals are being incorporated into maize. ProdiGene, the company at the centre of the current scandal has the greatest number of pharm crops and projects that 10 percent of the US maize will be devoted to biopharm products by 2010.

Far from supporting even weak containment strategies such as buffer zones, ProdiGene has told its shareholders it is hoping to "gain regulatory approval to lessen or abandon these requirements altogether".

Trials in other countries have also come to light. According to a recent report by Genetically Engineered Food Alert, a US-based coalition of environmental and consumer advocacy groups, Puerto Rico is one of four main centres in the US for these tests. The other three are the states of Nebraska, Wisconsin and Hawaii.

Another report by the same group reveals that these plants are by no means the only experimental GM crops grown in Puerto Rico. This Caribbean island has been host to 2,296 USDA-approved GM open-air field tests as of January 2001, making Puerto Rico host to more GM food experiments per square mile than any US state, except Hawaii.

Puerto Rico is not a state. Its residents are US citizens but have no voice or vote in the US Congress or in the UN.

Puerto Rico Farmers Association president Ramon Gonzalez revealed that he plants GM crops in his farm in the town of Salinas. He said that genetically modified crops in Puerto Rico are commercial and include a herbicide-resistant soya plant made by Monsanto (Roundup-ready) and a variety of corn that produces its own bio-pesticide, known as Bt corn.

According to Gonzalez, the harvested GM crops planted here are sold as seed to be planted elsewhere. "Puerto Rico is the preferred place to make seed because our weather permits us to have up to four harvests a year."

Local regulatory agencies seem to be unaware of the issue. A spokeswoman for the Puerto Rico Environmental Quality Board said that as Puerto Rico has no laws or regulations for GM crops, it has no mandate to intervene or investigate.

USDA spokesman Jim Rogers is reported to have said, "Nobody’s going to know all the possible risks", and "We mitigate these risks to what we feel is appropriate" [12].

On the contrary, we do know enough of the risks for such crops to be banned immediately. The USDA and other government regulators have been warned, and they should be held liable for all damages along with the companies involved.

  1. Ho MW and Steinbrecher RA. Fatal flaws in food safety assessment: critique of the joint FAO/WHO biotechnology and food safety report. Environmental & Nutritional Interactions 1998, 2, 51-84.
  2. "No vaccines in food plants!" by Joe Cummiins and Mae-Wan Ho, ISIS News 2000, 5 , ISSN: 1474-1547 (print), ISSN: 1474-1814 (online)
  3. "Poison pharm crops near you" by Joe Cummins, Science in Society 2002, 15 , 16.
  4. "FDA orders destruction of soybeans contaminated with genetically engineered corn" Associated Press, 11/12/2002
  5. "Another GM crop scare hits USA, GM "pharmaceutical maize contaminates soya", Friends of the Earth Press Release 15 November 2002.
  6. "Eat your cornflakes - and get vaccinated?" by Roberto Fernandez-Larsson AIDScience 11 April 2002.
  7. "Superbugs and superviruses from AIDS vaccines" by Mae-Wan Ho, ISIS News 2001, 9/10 , 15-6.
  8. Ho MW. Aids vaccine trials dangerous. ISIS News 2001, 11/12, ISSN: 1474-1547 (print), ISSN: 1474-1814 (online).
  9. "Edible AIDS vaccine or dangerous biological agent?" by Veljko Veljkovic and Mae-Wan Ho AIDScience 25 April, 2002.
  10. "Manufacturing Drugs and Chemicals in Crops: Biopharming Poses New Threats to Consumers, Farmers, Food Companies and the Environment" ;
  11. Norfolk Genetic Engineering Network ;
  12. "Biotech’s promise of turning farming into ‘pharming’" by Margaret Wertheim, LA Weekly, Oct 7, 2002 ;

Risks of Edible Transgenic Vaccines

Prof. Joe Cummins reviews recent developments in plant edible vaccines and points out some additional risks that have not been considered.

Using transgenic plants to produce vaccine cheaply has been the main area of molecular farming. A large number of transgenic plant vaccines are being developed and field tested [1,2].

Early tests of a hepatitis B vaccine in potato were hampered by the low levels of antigen produced in the plant, and by the safety requirement that only individuals previously immunized with injected vaccine should be exposed to the plant vaccine [3]. The main safety concern is that the oral vaccine preparations will induce "immune tolerance", thereby making the individual susceptible to the hepatitis B virus.

Oral tolerance is a fundamental biological response to ingested antigens, so that it is possible to eat proteins that would produce an immune response if injected. These difficulties appear to have cooled the fervour of clinical investigators and pharmaceutical companies. Though earlier, a vaccine for pig gastroenteritis produced in transgenic corn was claimed to be effective and ready for commercial release by 2003 [4].

Most transgenic plants have been produced using fertile plants, with crop isolation to limit pollen escape. Researchers have employed chloroplast transgene insertions to boost production levels and to limit the escape of modified genes in pollen. But chloroplast transgene containment is known not to be completely effective [5,6].

The two main concerns over transgenic vaccines are the contamination of food crops through cross pollination and of the vaccine itself in plant debris spreading as dust and as pollutants in surface and groundwater. The vaccine antigen may affect browsing animals and humans living in the area drinking vaccine-polluted water or breathing vaccine-polluted dust. The problem of inducing oral tolerance has already been pointed out above.

There is another kind of immune tolerance that could be acquired during embryogenesis. Burnet and Medawar found that the immune system established the difference between ‘self’ and ‘non-self’ molecules in the developing embryo (reviewed in reference [7]). Exposing the embryo to vaccine will cause the newborn to be tolerant to the vaccine and thus to regard both the vaccine and the infecting pathogen as ‘self’. Individuals born in the vaccine-polluted area may well not be able to produce antibodies to the vaccine antigen, and thus to lack protection against infection by the pathogen.

A number of transgenic plant vaccines currently being developed will be discussed. Cholera toxin gene was introduced into the chloroplast genome of the tobacco, the construction was geared towards high levels of vaccine-antigen production The chloroplast construction allowed 410 times higher antigen production than nuclear gene inserts [8].

Edible cholera B vaccines were produced in transgenic tomato [9,10]. And an antigen gene from the malaria parasite in transgenic tobacco has been proposed as a malaria vaccine [11].

Mice fed transgenic alfalfa with a gene for an antigen to foot and mouse virus were found to produce antibodies against the foot and mouth virus [12]. That study bears careful scrutiny because alfalfa pollen is known to spread to adjacent crops, and pregnant cows and sheep fed on the vaccine crop may give birth to offspring tolerant to the virus.

Transgenic tobacco was modified to produce vaccines against hepatitis B virus and cytomegalovirus. Virus-like particles were produced and concentrated in the tobacco seeds. However, the modified seeds did not provoke an immune response to hepatitis B and cytomegalovirus in mouse. Instead, a strong response to tobacco seed proteins was observed [13]. This unexpected result ought to serve as warning of the unpredictable risks inherent to the transgenic process.

A transgenic potato was loaded with genes for cholera, E.coli fimbrial antigens and rotavirus enterotoxin, and adult mice were found to produce antibodies to the toxins after feeding on the transgenic potatoes. Neonate mice passively immunized by suckling from mice fed transgenic potatoes had less diarrhea than neonates unexposed to the vaccine [14].

The alfalfa mosaic virus was used to produce rabies vaccine in spinach and tobacco [15]. The experiments progressed to having people eat spinach leaves (salad) containing the vaccine. Such vaccines with recombinant viral vectors should have been handled with very great care to prevent the viral vector from spreading or recombining and spreading to infect crops in the field. The rabies vaccination may be important for wild animals and humans, but problems associated with oral tolerance or exposure of children in the womb should be addressed before these vaccines are released to the environment, as the release could actually increase the spread of rabies.

Transgenic crop vaccines may be useful, but the risks to human health and the environmental are real.

It is imperative that the cultivation and production of pharm crops should be limited to controlled production facilities such as greenhouses, or better yet, in plant tissue culture, that prevent environmental release of the biopharmaceuticals.

Article first published 02/12/02


  1. Giddings G, Allison G, Brooks D and Carter A. Transgenic plants as factories for biopharmaceuticals" Nature Biotech 2000,18, 1151-6.
  2. Daniell H, Streatfield S, and Wycoff K. Medical molecular farming: production of antibodies, biopharmaceuticals and edible vaccines in plants. Trends in plant sciences 2001, 6, 219-27
  3. Mason H, Warzecha H, Mor T, and Arntzen C. Edible plant vaccines: applications for prophylactic and therapeutic molecular medicine. Trends in molecular medicine 2002,8, 324-30
  4. Bornetta L. Edible vaccines:not quite ready for prime time. Nature medicine 2002, 8, 94.
  5. Savoie K. Edible vaccine success. Nature Biotech 2000,18,367.
  6. " Pitfalls of Transgene Containment in Chloroplast " by Joe Cummins, ISIS Report 19th June 2002
  7. Quist,D. " Putting Genes in Chloroplast Not 'Environmentally Friendly' " ISIS Report 21st October 2002
  8. Metzinger P. The danger model: a renewed sense of self. Science 2002, 296,301-6.
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  10. Jano D, Meena L, Rizwan-Haq Q, SinghY, Sharma A, and Tyagi A. Expression of cholera toxin B subunit in transgenic tomato plants. Transgenic research 2002,11,447-54
  11. Ghosh S, Malhotra P, Lalitha P, Guha-Mukherjee S and Chauhan V. Expression of Plasmodium falciparum C-terminal region of merozoate surface protein (PfMSP1 19) a potential malaria vaccine candidate in tobacco. Plant Science 162,335-43
  12. Wigdorovittz A, Carillo C, DusSantos M, Trono K, Peralta A, Gomez M, Rios R, Franzone P, Sadir A, Escribana J, and Borca M. Induction of a protective antibody response to foot and mouth disease virus in mice following oral or parenteral immunization with alfalfa transgenic plants expressing the viral structural protein VP1. Virology 1999, 255, 347-53.
  13. Alli Z, Sardana R, Pierre B, Andonov A, Robert L, Scherthener J, Porter S, Dudani A, Ganz P, Tackaberry E and Altosaar I. Pharming vaccines for hepatitis and cytomegalovirus: toward the development of multivalent and subunit vaccines for oral delivery of antigens. Phytochemistry Reviews 2002,1, 55-66.
  14. Yu J and Landridge H, A plant–based multicomponent vaccine protects mice from enteric disease. Nature Biotech 2001, 19, 548-53.
  15. Yusibova V, Hoopera D, Spitsina S, Fleysha N, Keana R, Mikheevaa T, Dekaa D, Karaseva A, Coxa S, Randallb J and Kopr H. Expression in plants and immunogenicity of plant virus-based experimental rabies vaccine Vaccine 2002, 20 : 25-26

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