Enhanced immune reactions: intestinal bacteria can trigger autoimmune diseases

Immune system response: Intestinal bacteria can trigger autoimmune diseases

A recent study has shown that special intestinal bacteria trigger an immune system reaction, which in certain cases can lead to autoimmune diseases. The mechanism discovered could help develop a new approach to inflammatory bowel disease and other autoimmune diseases.

Gut bacteria have a huge impact on our health

Gut bacteria play an important role in our health. Among other things, they prevent infections and signal the immune system what to fight. They also support digestion and can help against obesity. However, some intestinal bacteria are also triggers of the yo-yo effect and can cause obesity, according to researchers. And a study by the University of Bern (Switzerland) and the University of Calgary (Canada) has now shown that special intestinal bacteria trigger an immune system reaction, which in certain cases can lead to autoimmune diseases.

New treatment options for autoimmune diseases

Researchers led by Andrew Macpherson and Kathy McCoy from the Department for BioMedical Research (DBMR) and the University Clinic for Visceral Surgery and Medicine at Inselspital Bern have discovered a function of intestinal bacteria that plays an important role in inflammatory bowel diseases.

Together with researchers from the University of Calgary, Canada, they describe a new mechanism in intestinal bacteria that regulates inflammatory cells.

"For the first time, it was demonstrated that special intestinal bacteria influence the immune system and thus also autoimmune diseases," said Andrew Macpherson in a message.

This opens up new therapeutic options for autoimmune diseases such as inflammatory bowel diseases (so-called inflammatory bowel diseases, IBD). The study was published in the "Cell" journal

Immune response too strong

So-called bacteroids, a special form of intestinal bacteria, live in symbiosis with humans and with mammals.

They produce a certain protein, integrase, that prevents chronic inflammatory bowel diseases by alerting white blood cells and causing them to destroy cells that can cause chronic inflammatory bowel diseases.

"We suspect that this mechanism prevents most people from developing these diseases," said Kathy McCoy.

However, there is a downside to this “alerting” by the protein integrase: in some people, the white blood cells overshoot in their fight against cells that could cause IBD.

This excessive immune reaction finally triggers intestinal diseases. Other autoimmune diseases such as diabetes are also caused by an overreaction of white blood cells.

Use "power" of the intestinal bacteria

"By showing how integrase works on the immune system, it becomes clear for the first time how gut bacteria affect chronic inflammatory bowel diseases," said McCoy.

"We specifically examined IBD, but it can be assumed that there are other proteins in the intestine that work similarly to integrase and other autoimmune diseases such as diabetes," added Francesca Ronchi from DBMR and Inselspital, co-first author of the study.

Such proteins could be used to use the "power" of the intestinal bacteria and to combat inflammatory bowel diseases and other autoimmune diseases. (ad)

Author and source information

Video: Dan Littman NYU. HHMI 2: Shaping of Immune Responses by the Microbiota (January 2022).