Date:

March 8, 2018

Source:

Yale University

Summary:

Bacteria found
in the small intestines of mice and humans can travel to other organs and
trigger an autoimmune response, according to a new study. The researchers also
found that the autoimmune reaction can be suppressed with an antibiotic or
vaccine designed to target the bacteria, they said.

Bacteria found in the small intestines of mice and humans can travel to
other organs and trigger an autoimmune response, according to a new Yale study.
The researchers also found that the autoimmune reaction can be suppressed with
an antibiotic or vaccine designed to target the bacteria, they said.

The findings, published in Science, suggest promising new approaches
for treating chronic autoimmune conditions, including systemic lupus and
autoimmune liver disease, the researchers said.

Gut bacteria have been linked to a range of diseases, including autoimmune
conditions characterized by immune system attack of healthy tissue. To shed
light on this link, a Yale research team focused on Enterococcus gallinarum, a
bacterium they discovered is able to spontaneously “translocate”
outside of the gut to lymph nodes, the liver, and spleen.

In models of genetically susceptible mice, the researchers observed that in
tissues outside the gut, E. gallinarum initiated the production of
auto-antibodies and inflammation — hallmarks of the autoimmune response. They
confirmed the same mechanism of inflammation in cultured liver cells of healthy
people, and the presence of this bacterium in livers of patients with
autoimmune disease.

Through further experiments, the research team found that they could
suppress autoimmunity in mice with an antibiotic or a vaccine aimed at E.
gallinarum. With either approach, the researchers were able to suppress
growth of the bacterium in the tissues and blunt its effects on the immune
system.

“When we blocked the pathway leading to inflammation, we could reverse
the effect of this bug on autoimmunity,” said senior author Martin
Kriegel, M.D.

“The vaccine against E. gallinarum was a specific approach, as
vaccinations against other bacteria we investigated did not prevent mortality
and autoimmunity,” he noted. The vaccine was delivered through injection
in muscle to avoid targeting other bacteria that reside in the gut.

While Kriegel and his colleagues plan further research on E. gallinarum and
its mechanisms, the findings have relevance for systemic lupus and autoimmune
liver disease, they said.

“Treatment with an antibiotic and other approaches such as vaccination
are promising ways to improve the lives of patients with autoimmune
disease,” he said.

Story Source:

Materials provided by Yale University. Original written by Ziba Kashef. Note:
Content may be edited for style and length.

Journal Reference:

1.   
S. Manfredo
Vieira, M. Hiltensperger, V. Kumar, D. Zegarra-Ruiz, C. Dehner, N. Khan, F. R.
C. Costa, E. Tiniakou, T. Greiling, W. Ruff, A. Barbieri, C. Kriegel, S. S.
Mehta, J. R. Knight, D. Jain, A. L. Goodman, M. A. Kriegel. Translocation of
a gut pathobiont drives autoimmunity in mice and humans. Science,
2018; 359 (6380): 1156 DOI: 10.1126/science.aar7201