Gut bacteria can trigger autoimmune response
Our immune system is a collection of cells and chemicals that defend the body and will fight any invading infection-causing agents such as bacteria and viruses.
But when our immune system mistakenly attacks our own tissues, an autoimmune disorder occurs.
Gut bacteria has been linked to many diseases and there have been multiple associations between gut microbiota and the occurrence of auto immune conditions but this association is poorly understood.
The researchers found that this bacterium could travel outside the gut to lymph nodes, the liver and the spleen.
Researchers from Yale University focussed on a particular bacterium called Enterococcus gallinarum.
In models of genetically susceptible mice, the researchers observed that in the tissues outside the gut, Enterococcus gallinarum triggered the production of auto-antibodies and inflammation. These are characteristics of an autoimmune response.
Researchers confirmed the presence of this bacterium in the livers of patients with autoimmune disease, but not in healthy controls. However the same mechanism of inflammation was found in cultured liver cells of healthy people.
The researchers found that this bacterium could travel outside the gut to the lymph nodes, the liver and the spleen.
Through further experiments, the researchers could suppress autoimmunity in mice with an antibiotic or a vaccine that targets E. gallinarum.
Both methods could suppress the growth of the bacterium and reduce its effect on the immune system.
The vaccine used was a specific vaccine that targets E. gallinarum only and avoids other bacteria that reside in the gut. The researchers found that vaccinations against other bacteria did not prevent autoimmunity or mortality.
The study shows how bacteria can travel to other organs and trigger an autoimmune response and can be used to initiate new approaches to treating chronic autoimmune diseases such as systemic lupus and autoimmune liver disease.
Treating people with autoimmune diseases with an antibiotic or vaccination can easily improve the lives of these patients.
Source: Science
