Anti-allergenic microbes
Intestinal bacteria protecting against food allergies have been found
Copper news based on ScienceDaily: Gut bacteria that protect against food allergies identifiedThe presence of conditionally pathogenic bacteria of the genus Clostridia in the intestinal microflora protects against food allergies, researchers from the University of Chicago found out during experiments on mice.
By triggering an immune response that prevents allergens from entering the bloodstream, clostridia minimize their effects and prevent sensitization – a key stage in the development of food allergies. The discovery, whose results are published in the journal Proceedings of the National Academy of Sciences (Stefka et al., Commercial bacteria protect against food allergen sensitization), suggests the possibility of preventive probiotic therapy of acute allergic reactions to food.
The causes of food allergies – in some cases, resulting in a fatal inadequate immune response of the body to certain types of food – are unknown. At the same time, the results of previous studies suggest that a significant impact on the significant increase in recent years in the prevalence of food allergies in developed countries, especially among children – so, according to the Centers for Disease Control and Prevention of the United States (CDC), this figure increased by 18 percent from 1997 to 2007, have hygienic and dietary habits that violate the normal composition of the intestinal microflora, as well as the widespread use of antimicrobial drugs.
"Environmental factors such as unjustified prescribing of antibiotics, fatty foods, the prevalence of cesarean section, insufficient contact with common pathogens, artificial feeding – all of them affect the composition of the bacterial community present in the intestine, – said the head of the work Catherine Nagler (Kathryn Nagler). "Our results suggest that the consequence of this development is an increased susceptibility to food allergies."
Nagler and her colleagues, in order to study the effect of intestinal bacteria on the severity of the immune system's response to food, exposed mice raised in sterile conditions, which completely lacked resident microorganisms, and mice exposed to peanut allergen immediately after birth to antibiotic therapy. The organisms of both groups of animals demonstrated the strongest immune response, producing significantly higher levels of antibodies to the allergen than mice with normal intestinal microflora.
Experiments have shown that the level of sensitization (increasing the reactive sensitivity of the body to foreign agents) decreases when conditionally pathogenic bacteria of the genus Clostridia are introduced into the intestinal microflora of animals. These microorganisms are usually part of the normal flora of the gastrointestinal tract, some of them, under certain conditions, produce the most powerful of the known poisons - botulinum toxin, tetanospasmin and others. As the researchers found, the return of intestinal bacteria belonging to another common genus, Bacteroides, to the microflora of mice did not cause an effect similar to the introduction of clostridium, which led to the assumption of a unique protective role of the latter in food allergies.
To identify the biological mechanism underlying this phenomenon, Nagler and her colleagues conducted a genetic analysis of the immune response to the presence of clostridium in the intestine at the cellular and molecular level. The analysis showed that the bacteria cause local immune cells to synthesize high levels of interleukin 22 (IL-22), a signaling molecule that reduces the permeability of the intestinal mucosa. Experiments on mice that underwent antibiotic therapy immediately after birth demonstrated that artificial administration of IL-22, as well as colonization of the intestine with clostridium, reduces the level of presence of antibodies to the peanut allergen in the blood of animals. At the same time, this indicator increased sharply when IL-22 was neutralized, which proves, the researchers concluded, the protective role of this intercellular interaction protein, which prevents the allergen from entering the bloodstream.
Based on the results obtained, Nagler and her colleagues are currently working on the development and testing of probiotic compositions including clostridium that could be used for preventive therapy of food allergies.
Portal "Eternal youth" http://vechnayamolodost.ru26.08.2014