A team published their results in Science Immunology to examine whether intestinal microbes influence vulnerability to secondary bacterial infections after a respiratory virus. They studied segmented filamentous bacteria (SFB) in mice infected with influenza A and then exposed the animals to common respiratory bacterial pathogens.
The investigators used several bacteria that commonly cause post-influenza pneumonia. They found that SFB gave marked protection against these highly lethal secondary infections. The protective effect worked through lung immune cells: SFB altered the behaviour of alveolar macrophages so the cells resisted the dysfunction that normally follows influenza.
Lead author Vu Ngo noted that adding one gut species changed how lung macrophages respond. Senior author Andrew T. Gewirtz said the team hopes to use this mechanism to develop new treatments. The study was funded by NIAID of the NIH.
Difficult words
- intestinal — relating to the intestines or the gut
- microbe — very small living organism, often single-celledmicrobes
- vulnerability — a condition of being easily harmed or infected
- secondary — happening after an earlier event
- pathogen — a microbe that causes disease in a hostpathogens
- alveolar macrophage — an immune cell in the lungs that eats microbesalveolar macrophages
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Discussion questions
- How could a single gut species change the behaviour of immune cells in the lungs? Give one possible explanation.
- Would you support developing treatments based on gut microbes? Why or why not?
- How might these findings change care for people who have had influenza?
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