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| By William H. R. Langridge |
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| Scientists today are working not only on the development of new vaccines against diseases that still make people sick, but also on finding unique ways of getting those vaccines into people. |
| The production of edible vaccines is an outgrowth of genetic engineering. |
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Genetic engineering is the deliberate, controlled manipulation of the genes in an organism with the intent of making that organism better in some way. This is usually done independently of the natural reproductive process |
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| The technique has been dubbed "farming." Rather than manipulating plants to make a firmer tomato or a sweeter peach, "farmers" insert genes that instruct a plant to manufacture pharmaceutical compounds. In the future they envisage, flu shots will be replaced by bananas. Prozac, anyone? Try this corn puff. Farmers dream that all drugs will ultimately be delivered in snacks.In theory, just about any drug can be engineered in a kernel of corn or a grain of rice. |
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| First out of the pipeline will be vaccines. In August, industry leader ProdiGene began Phase I clinical trials on a vaccine against traveler's diarrhea. Resulting from a dismal species of E. coli, the condition is also a prime cause of infant mortality in many developing nations. Instead of pursuing the regular path of cell-culturing and purification, Texas-based ProdiGene hopes to deliver a vaccine in a simple kernel of corn. |
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1. Which E. coli gene/genes have been inserted into plant cells? |
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| 2. Which E. coli gene/genes have been inserted into plant cells? |
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| 3. Why were these gene/genes chosen?
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| 4. HOW is the immunity developed?
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| 5. What are the advantages of making vaccine-containing foods?
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| 6.What are the possible dangers of using vaccine-containing foods?
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|  You will find answers to these questions at the following websites
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| Animal Cell Technology: becoming more and more important |
| The vectors carrying the genes: |
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Figure 1
Principle of DNA vaccination. An immunogenic gene is inserted into an expression plasmid (A), which is inserted into cultured cells (B). The cells are screened for expression of the gene protein and then cultured. The plasmid DNA is then extracted from (more ...) |
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Figure 2
Principle of delivering vaccines in edible plants. A gene from a human pathogen is inserted into a bacterium that infects plants (A). The bacterium then infects cultured leaf segments of the selected food plant (B), which sprout into whole plants containing the human pathogen gene (C). Once the plant is eaten, it triggers an immune response to the pathogen. |
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| From:http://www.pubmedcentral.gov/articlerender.fcgi?artid=1123275 |
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| Some researchers point to the dangers of edible vaccines. They say that the idea of helping the Third World with transgenic vaccines is little more than a ruse. It is in essence selling biotechnology on the backs of the poor. Those researchers point out that to be medically effective, drugs have to be delivered in the right dose. How would people know how much they were supposed to eat? A whole banana, half a banana? Who's to say? More critical, how could you be sure that people wouldn't overdose? How would they even know they were eating the right variety? After all, a genetically modified banana looks just like a regular one. |
| Those researchers are skeptical of the medical miracle promised by companies like ProdiGene and suspect that a lot of the naively optimistic ideas being bandied about will "never see the light of day" as commercial products. |