Soy and asthmatic mice: about the danger in genetically modified plants

The opponents of genetically modified plants claim that this is proof of the ability of genetically modified plants to create allergies in animals. The supporters reply that there has never been any doubt that even genetically modified plants can cause allergies and one simply needs to warn against them

In the first chapter We checked whether there is any truth behind Greenpeace's claims against genetic engineering in food plants. according to which the genetically modified plants are poisonous. This time we will examine the subject of allergy.

In the early XNUMXs, Pioneer decided to develop a genetically engineered strain of soy that would be particularly suitable for animal consumption, especially chickens. Pioneer's engineers knew that adequate amounts of the amino acid methionine were added to the food the chickens received, and these food additives cost a lot of money. They decided that the new strain of soybean would already produce the necessary methionine by itself, and for that they inserted into the plant a gene originally taken from Brazil nuts.

The product developed nicely. It grew to glory, and was even rich in methionine. But Pioneer decided to test the allergenicity (ability to cause allergies) of their new plant, and they discovered a terrible thing - it provoked immune reactions in humans, the kind that cause allergies and possibly even autoimmune diseases, in which the immune system inadvertently attacks the body itself.

Sound terrible? very But fortunately, these effects only occurred in people who were allergic to Brazil nuts in the first place.

What went wrong with Pioneer's plant?

To understand what happened, we must first realize that some people in the population are allergic to some food. In the United States, approximately six percent of the population is allergic to one type of food or another. Allergy has nothing to do with genetic engineering. It is caused as a result of the body learning to react to certain substances found in food, and treat them as allergens - that is, allergy factors. When these substances enter the body, they provoke a response from the immune system, which jumps into action while causing us to tear, runny nose and even edema that can block the airway in extreme situations.

When Pioneer's engineers decided to transfer one of the genes from Brazil nuts to soybeans, they ignored the fact that this gene produces a protein that is present in Brazil nuts and tends to cause allergies in humans. Not in everyone - in fact, it causes an allergy in only a few - but it can certainly be considered an allergen: an allergy factor. If the plant were released into the world's air, most likely humans would also be exposed to it - especially the chickens that feed the birds - and some of them would develop an allergy to it.

Pioneer decided not to take any chances, and completely canceled further development. Pioneer's experimental GM soybeans never made it to market. The project ended at that point, and was never renewed.

The danger of allergy

Pioneer's soy allergen story is interpreted positively or negatively, depending on who hears it. The opponents of genetically modified plants claim that this is proof of the ability of genetically modified plants to create allergies in animals. The supporters reply that there was never any doubt that even genetically modified plants can cause allergies - just like normal plants - and that the government regulatory procedure worked well in this case and managed to locate the allergenic plant before it was released on the market.

The very existence of the discussion on the subject should keep sleep from the eyes of every person exposed to genetically modified plants. And we are all like that. 81% of the soy crops in the current era are genetically modified, as well as 64% of the cotton and 29% of the corn. We are all exposed to the products of genetically modified plants, whether they end up in our food, our clothes, or the cows and chickens that feed on them. If one of the plants turns out to be a cause of allergy, there is a danger to a large number of people.

Is allergy really such a serious threat to our health? Well, there is no doubt that there are worse diseases, but even a severe allergy attack can be life-threatening. In the most severe cases, edema and swelling develop in the throat, which presses on the trachea and causes death by suffocation. In the United States, up to two hundred people die each year as a result of accidental exposure to allergens, and more than one hundred thousand people visit hospitals to treat severe allergy symptoms.

And now that we understand the danger, the question arises: how do you make sure that new genetically modified plants are not allergenic?
Law and Order

It is clear to all the countries that it is not possible to blindly trust the biotech companies to inspect themselves and avoid the release to the market of transgenic plants that have not been properly tested. Because of this, supervision and control are imposed on the companies, and every new plant that should enter the market goes through a procedure of tests and approvals. I'll go ahead and say that this procedure seems arduous and excessively long to many scientists, while others argue that it is not rigorous and extensive enough. Either way, this is the procedure as described in an academic review article on the subject.

The government inspection begins by reviewing the known history of the new gene appearing in the transgenic plant. This gene is usually taken from existing organisms: bacteria, other plants, fungi or animals. If people have been exposed to the products of this gene in the past, it is possible to know whether it tends to trigger an allergy in them. The gene products are also tested, to see if they are similar in shape to other substances that cause allergies. Genes that come from wheat or its relatives are tested to make sure they do not cause celiac disease, which results from sensitivity to certain proteins in wheat.

The European Union, like individual countries and the US, has strict rules for testing genetically modified plants. Originally from Flickr.

What happens if the tests show that the transferred gene is suspected to be an allergen? In this case, blood samples are taken from individuals suffering from the appropriate type of allergy, and mixed with the products of the suspect gene to check whether an allergic reaction is obtained.

This procedure was the basis of the tests that proved the allergenicity of the soy from the beginning of the article, an allergenic gene that came from Brazil nuts was inserted into it. I mean, he proved himself in at least one case.

What else? The test described only refers to the history of the new gene inserted into the plant. Only if its history indicates a serious fear of being an allergen, is the new plant tested in actual experiments on humans with the potential to develop an allergy. Why is this so problematic? Because sometimes, 'foreign' genes inserted into genetically modified plants can result in significantly different products than expected.
The mouse and the pea

In 2005, ten years after the Pioneer soybean incident, scientists saw a strange sight in one of the pea fields grown by the Australian Scientific and Industrial Research Organization. We do not have exact details, but it is likely that the mice in the same field tended to suffer from shortness of breath and a variety of other symptoms that characterize allergies. The pea - genetically engineered, of course - caused allergies in the mice!

The discovery caused an immediate halt to work on the pea variety in question. The reasons are understandable. We know that mice are similar to us in many ways, being distant relatives on the tree of life. Substances that cause an allergy in the small rodents, may cause a similar allergy in humans as well. Since this is the case, it is clear why the work was stopped. Another fact was less clear: what caused the allergy?

In the earlier case of the soy, it was clear that the protein transferred from Brazil nuts was the one that caused the allergy, because it was also responsible for allergy cases caused by eating Brazil nuts. But the protein added to the genetically engineered peas was not originally allergenic. Only when it was expressed inside the pea did the protein acquire new and malicious allergenic properties.

Genetically modified pea plants caused allergic symptoms in mice.

To a large extent, this is the worst dream of every genetic engineer. We understand that the living cell is an extremely complex machine, containing billions of proteins. Each of the proteins can react with some of the other proteins, cut them, add parts to them or fundamentally change their shape. Any new protein added to the cell - through genetic engineering, for example - may undergo changes and improvisations by the other proteins. These changes may cause it to take on a form that will harm the body. For example, as an allergy cause in the best case, or as a poison in the worst case.

Of course, the case must be taken in proportion: the allergenicity of the plants was not to humans, but to mice, and it was discovered within a relatively short period of time, and before the plant was released to the farmers and the general public. Even if it had reached the public, there is no certainty that the plant would have caused an allergy in humans, and not only in mice. To this must be added the fact that since 2005 until now, no other genetically modified plant with allergenic properties has been discovered. That is, the phenomenon of de novo (new) allergenicity is relatively rare, and certainly does not characterize all genetically modified plants.
Summary

In this article we reviewed two different cases in which genetically modified plants caused allergies in mammals. In the first case, the danger was identified in advance by the biotech company that acted according to the procedures outlined by the authorities. Accordingly, the transgenic plant was never released on the market. In the second episode, the cause of the allergy was not predicted in advance, and although it has never been proven to be allergenic for humans as well, it is still appropriate that this episode should be a kind of 'wake-up call' for many of the supporters of genetically modified plants. These plants are not necessarily safe, and it is appropriate to call for more rigorous experiments before introducing them to the market.

Unfortunately, and as often happens in debates on the subject, both Greenpeace (as representing the greens) and some skeptics prefer to choose the extreme and stick to it by default: the former avoid genetically modified plants as if they were black magic, and the latter support their introduction into the market with a minimum of tests or control. In my opinion, both are wrong. Genetically engineered plants hold great promise (which we will discuss in detail in the following articles) for health and the environment, but there is also a constant and justified concern - even if very small - regarding the health danger they hold.

The solution, as always, lies in the small details. Instead of being satisfied with checking the history of the gene transferred to the plant, the allergenicity and toxicity of its products should be checked in experiments on animals, on human blood (which may show signs of allergy) and on humans who volunteer to participate in the experiment, just as is done in drug testing. This means that the costs of developing and approving new genetically modified plants will skyrocket, and the time required to approve them will be extended by a year or two, but perhaps in this way we will avoid the next health disaster.

For the first article in the series - are genetically engineered plants toxic - click here