A Study Sheds Light on How Good Bacteria Prevent Intestinal Inflammation

By Sally Robertson, BSc July 4, 2018

Researchers at Baylor College of Medicine have identified the mechanism by which good bacteria (microbiota) help maintain a healthy gut.

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The study, recently published in the journal Immunity shows that the microbiota balances intestinal immune responses and protects against inflammation through their interaction with Epithelial cells and immune cells

The results suggest that manipulating these good bacteria to minimize immune responses could benefit people with inflammatory bowel disease.

Gretchen Diehl, author of the study, says that microbes like salmonella cause a strong inflammatory immune response designed to kill the microbe, but this response can also damage healthy tissue.

The microbiota attenuates this response by triggering the presentation of the antigen. lls (APC) to release the cytokine IL-10, which regulates T cell responses to prevent inflammation.

The result, says Diehl, is a balanced response that can still fight an infection like Salmonella but this is regulated to prevent damage to healthy intestinal tissue.

Here, we defined the role of the microbiota in modulating the immune response in a way that reduces inflammation and limits the damage it can cause to the intestine. "[19659012] Gretchen Diehl, author of the study

To find out how the microbiota triggers this response, Diehl and his colleagues studied what happens when they administer antibiotics to laboratory animals. The team found that among the animals that received the antibiotics, the APCs did not produce IL-10.

The researchers transferred the bacteria to the animal's gut and discovered that only bacteria capable of interacting with intestinal epithelial cells could trigger.

It is somewhat counterintuitive because microbes that can attach to the intestinal epithelium are considered pathogens which may potentially cause the disease.

But in this case we found that the attachment of bacteria to the epithelium did not cause disease; instead, it was necessary to promote a disease. Balanced regulation of T cell responses and protect the intestine. "

Gretchen Diehl, author of the study

The researchers will now explore the signaling pathways that activate the epithelium, in the hope of identifying new pathways that can be manipulated to balance the immune response