mrz
10-07-03, 22:36
GM vaccine for peanut allergy shows promise
18:42 10 July 03
NewScientist.com news service
A new vaccine based on genetically modified peanut proteins could protect people with peanut allergies from developing a life-threatening allergic response, suggests a new study.
Researchers successfully used the vaccine in mice, and human trials could begin within a year, they say.
Many allergies such as hayfever are treated through desensitization - that is, allergic people are exposed repeatedly to the allergen, and eventually their immune systems learn not to overreact to its presence.
But because peanut allergy is potentially fatal, doctors have not been willing to risk this approach with peanuts.
The US team altered the allergenic proteins in peanuts in such a way that they could be recognized by the immune system without provoking a life-threatening reaction. They used the altered proteins to build up a tolerance in the mice's immune systems which carried over to natural unaltered peanut proteins.
About 2 percent of people are sensitive to peanuts to some degree. Peanut allergies kill about 50 people a year in the United States alone, and account for 15,000 emergency room visits.
Weaker response
The allergic reaction happens when antibodies called immunoglobulin E (IgE) detect a foreign particle or allergen in the body and prompt the release of histamine molecules - which make the airways constrict and the blood vessels dilate. Although this is part of a normal immune response, in allergic people the body overreacts, causing a potentially fatal condition called anaphylaxis.
The researchers genetically altered three allergenic peanut proteins so that they did not have the receptor that IgE recognizes. Then they created a strain of Escherichia coli bacteria that produced these proteins, killed the bacteria, and administered the GM proteins rectally to mice. Because IgE could not recognise the altered proteins there was no allergic reaction.
However, other parts of the immune system do recognize the proteins, and respond by turning down the IgE response and turning up a reaction from another part of the immune system mediated by a white blood cell called TH1. Later, when the immune system detects regular peanut protein, the IgE response is much weaker than before and the TH1 response is stronger.
It is not clear yet why this happens. But it seems that a strong response from the TH1-mediated part of the immune system dampens a response from the other part of the immune system, which is mediated by white blood cells known as TH2 cells.
Hugh Sampson, at the Mount Sinai School of Medicine in New York, and one of the team says they plan to begin human trials within about a year. If approved, the treatment might provide only partial protection, but importantly it will still prevent an allergic reaction from being fatal, he says.
William Cookson of the Wellcome Trust Centre for Human Genetic Disease in Oxford, UK cautions that a therapy that works in mice still might not work in humans. He said a similar approach to treating cat allergy had recently been a failure.
Journal reference: Journal of Allergy and Clinical Immunology (vol 112, p 159)
Kurt Kleiner
http://www.newscientist.com/news/news.jsp?id=ns99993930
Nu alleen nog oplossing voor dat je taaie slap vlees wordt van soja... :rolleyes:
Oh, en niet te vergeten dat GM-gras. Vraag me af of je daar dan ook nog steeds zoveel energie uit kan halen dat eten overbodige luxe is.
A new vaccine based on genetically modified peanut proteins could protect people with peanut allergies from developing a life-threatening allergic response, suggests a new study.
Haha, bedreig ik levens dan met mijn allergische reactie op de letters G en M? :moe:
18:42 10 July 03
NewScientist.com news service
A new vaccine based on genetically modified peanut proteins could protect people with peanut allergies from developing a life-threatening allergic response, suggests a new study.
Researchers successfully used the vaccine in mice, and human trials could begin within a year, they say.
Many allergies such as hayfever are treated through desensitization - that is, allergic people are exposed repeatedly to the allergen, and eventually their immune systems learn not to overreact to its presence.
But because peanut allergy is potentially fatal, doctors have not been willing to risk this approach with peanuts.
The US team altered the allergenic proteins in peanuts in such a way that they could be recognized by the immune system without provoking a life-threatening reaction. They used the altered proteins to build up a tolerance in the mice's immune systems which carried over to natural unaltered peanut proteins.
About 2 percent of people are sensitive to peanuts to some degree. Peanut allergies kill about 50 people a year in the United States alone, and account for 15,000 emergency room visits.
Weaker response
The allergic reaction happens when antibodies called immunoglobulin E (IgE) detect a foreign particle or allergen in the body and prompt the release of histamine molecules - which make the airways constrict and the blood vessels dilate. Although this is part of a normal immune response, in allergic people the body overreacts, causing a potentially fatal condition called anaphylaxis.
The researchers genetically altered three allergenic peanut proteins so that they did not have the receptor that IgE recognizes. Then they created a strain of Escherichia coli bacteria that produced these proteins, killed the bacteria, and administered the GM proteins rectally to mice. Because IgE could not recognise the altered proteins there was no allergic reaction.
However, other parts of the immune system do recognize the proteins, and respond by turning down the IgE response and turning up a reaction from another part of the immune system mediated by a white blood cell called TH1. Later, when the immune system detects regular peanut protein, the IgE response is much weaker than before and the TH1 response is stronger.
It is not clear yet why this happens. But it seems that a strong response from the TH1-mediated part of the immune system dampens a response from the other part of the immune system, which is mediated by white blood cells known as TH2 cells.
Hugh Sampson, at the Mount Sinai School of Medicine in New York, and one of the team says they plan to begin human trials within about a year. If approved, the treatment might provide only partial protection, but importantly it will still prevent an allergic reaction from being fatal, he says.
William Cookson of the Wellcome Trust Centre for Human Genetic Disease in Oxford, UK cautions that a therapy that works in mice still might not work in humans. He said a similar approach to treating cat allergy had recently been a failure.
Journal reference: Journal of Allergy and Clinical Immunology (vol 112, p 159)
Kurt Kleiner
http://www.newscientist.com/news/news.jsp?id=ns99993930
Nu alleen nog oplossing voor dat je taaie slap vlees wordt van soja... :rolleyes:
Oh, en niet te vergeten dat GM-gras. Vraag me af of je daar dan ook nog steeds zoveel energie uit kan halen dat eten overbodige luxe is.
A new vaccine based on genetically modified peanut proteins could protect people with peanut allergies from developing a life-threatening allergic response, suggests a new study.
Haha, bedreig ik levens dan met mijn allergische reactie op de letters G en M? :moe: