|Leading scientists concerned about potential allergenicity of GM rice (13/9/2006)|
GM WATCH: About a week ago Greenpeace International announced that illegal GM rice from China had been found in food products in France, Germany and the UK.
The following statement by 3 leading international scientists shows that this unapproved experimental rice contains a toxin with significant potential allergenicity.
Scientists' statement from:
Available at http://www.greenpeace.org/international/press/reports/ScientistStatementHealthConcernsGErice
Statement on the potential allergenicity of the Bt toxin, Cry1Ac
We, the undersigned, note with concern the recent discoveries of contamination of rice1 and rice products, including baby food2, with an experimental genetically engineered (GE) rice. The GE rice contains a gene for the Cry1Ac protein, or possibly for a fusion Cry1Ab/Cry1Ac protein with similar immunogenic properties to Cry1Ac3.
Cry1Ac has not been approved for human consumption in any food crop and there is concern over its potential allergenicity.
Research4 into the gene for Cry1Ac has found that
1. Cry1Ac protoxin is a potent immunogen.
2. The protoxin is immunogenic by both the intraperitoneal (injected) and intragastric (ingested) route. 3. The immune response to the protoxin is both systemic and mucosal. 4. Cry1Ac protoxin binds to surface proteins in the mouse small intestine, and this could induce mid or long-term effects on mammalian health.
Therefore, we urge the developers and regulatory authorities of this GE rice to proceed with caution with the use of the gene for the Cry1Ac in any part of the genetic construct within the GE rice. It is possible that humans, in particular sub-populations such as infants and small children could be exposed to immunogenically-significant amounts of Cry proteins contained in foods.
A thorough evaluation of its food safety prior to any import, consumption, approval or further development of this GE rice would be necessary as rice is a staple food crop. Studies following the steps recommended by the FAO/WHO expert consultation5 to evaluate allergenicity should be conducted by independent scientists, and their results published in peer-reviewed journals to allow evaluation of food safety. In addition, further studies into the potential allergenicity of Cry1Ac and other Bt proteins should be undertaken as a matter of the utmost urgency.
Pr. Ian F.Pryme
Dr. Christian Velot
1. Zi, X. (2005) GM rice forges ahead in China amid concerns over illegal planting. Nature Biotechnology 23: 637.
3. Tu, J., Zhang, G., Datta, K., Xu, C., He, Y. Zhang, O., Khush, G. & Datta, S.K. (2000) Field performance of transgenic elite commercial hybrid rice expressing Bacillus thuringiensis-endotoxin. Nature Biotechnology 18: 1101-1104.
4 Moreno-Fierros, L. Garcia, N. Gutierrez, R. Lopez-Revilla, & R. Vazquez-Padron, RI.(2000) Intranasal, rectal and intraperitoneal immunization with protoxin Cry1Ac from Bacillus thuringiensis induces compartmentalized serum, intestinal, vaginal and pulmonary immune responses in Balb/c mice. Microbes Infect 2: 885-90; Vazquez-Padron, R.I, Moreno-Fierros, L. Neri-Bazan, L, de la Riva, G.A & Lopez-Revilla, R. (1999) Bacillus thuringiensis Cry1Ac protoxin is a potent systemic and mucosal adjuvant. Scand J Immunol 49: 578-584; Vazquez-Padron, R.I Moreno-Fierros, L. Neri-Bazan, L, de la Riva, G.A & Lopez-Revilla, R. (1999) Intragastric and intraperitoneal administration of Cry1Ac protoxin from Bacillus thuringiensis induces systemic and mucosal antibody responses in mice. Life Sciences 64: 1897-1912; Vazquez-Padron, R. I., Moreno-Fierros, L. Neri-Bazan. L. Martínez-Gil, A.F., de la Riva, G.A. & Lopez-Revilla, R. (2000) Characterization of the mucosal and systemic immune response induced by Cry1Ac protein from Bacillus thuringiensis HD 73 in mice. Braz J Med Biol Res 33: 147-155; Vazquez-Padron, R. I., Gonzales-Cabrera, J., Garcia-Tovar, C. Neri-Bazan, L., Lopez-Revilla, R., Hernandez, M., Moreno-Fierros, L. & de la Riva.G.A. (2000) Cry1Ac protoxin from Bacillus thuringiensis sp. kurstaki HD73 binds to surface proteins in the mouse small intestine. Biochem Biophys Res Comms 271: 54-58. Guerrero, G. G., Dean, D.H. & Moreno-Fierros, L. (2004) Structural implication of the induced immune response by Bacillus thuringiensis Cry proteins: role of the N-terminal region. Molecular Immunology 41: 11771183.
5. FAO/WHO 2001. Evaluation of allergenicity of genetically modified foods. Report of a joint FAO/WHO expert consultation on allergenicity of foods derived from biotechnology, 22 25 January 2001. Rome, Italy.