AsianScientist (Jan. 15, 2015) – Scientists have identified the tissues responsible for driving intestinal damage caused by egg white allergies, paving the way for tissue-targeted treatments. The study documenting these findings has been published in PLOS ONE.
In an experimental model of food allergy, mice expressing the T-cell receptor specific for the egg allergen ovalbumin developed intestinal inflammation after being fed with egg white. However, prolonged feeding with egg white led to immune tolerance and reduced inflammation. University of Tokyo researchers led by Haruyo Nakajima-Adachi have shown that IL-4, a cytokine produced by a type of white blood cell (CD4+ T-cell), is essential for the onset of intestinal damage (enteropathy).
In order to identify the immune system mechanisms involved in the onset and suppression of enteropathy, the research group created transgenic mice deficient in various lymphoid tissues, namely the mesenteric lymph nodes (MLNs), Peyer’s patch (PPs), MLNs and PPs (pLNs) and the spleen.
They showed that in the intestinal immune tissues, MLNs are critically required for the onset of enteritis, but PPs, lymph node-like organs in the intestinal tract, react quickly to the ingested ovalbumin and function cooperatively with MLNs. The study also revealed that spleen tissue promptly acquired tolerance to ingested ovalbumin and were not involved in the development of enteropathy.
Lastly, they found that persistent inflammatory responses continued in the mesenteric lymph nodes, even after the establishment of strong systemic tolerance to ingested ovalbumin. The authors suggest that the minor and persistent inflammatory responses found in the mesenteric lymph nodes after tolerance induction may be involved in the reemergence of enteropathy.
The study demonstrates how the immune system can initiate the conflicting responses of inflammation and tolerance to ingested food. When this complex immune system balance breaks down, food allergies are caused in patients, but the detailed mechanism remains unknown. The present study has elucidated which tissues are involved and how they are interrelated, and is a major contribution to the development of safe and effective treatments based on solid scientific evidence.
The article can be found at: Nakajima-Adachi et al. (2015) Peyer’s Patches and Mesenteric Lymph Nodes Cooperatively Promote Enteropathy in a Mouse Model of Food Allergy.
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Source: University of Tokyo.
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