Nav: Home

Humans use 'sticky molecules' to hang on to good bacteria in the gut

March 24, 2016

Scientists have long known that our bodies need to control the communities of bacteria in the gut to prevent a beneficial environment from turning into a dangerous one. What hasn't been known is how we do this.

Now, Oxford University researchers have proposed a clever solution to the problem: make good bacteria sticky so they don't get lost. The key to this is for a host to target good bacteria over bad ones - potentially via the immune system, which produces highly-specific adhesive molecules called immunoglobulins (specifically 'IgA') that coat the bacteria in the gut.

The research is published in the journal Cell Host and Microbe.

Co-lead author Kirstie McLoughlin, of the Department of Zoology at Oxford University, said: 'We carry with us vast communities of bacteria that live on us and inside us, particularly in our intestines. These bacteria perform many functions for us, such as breaking down our food, helping our immune system develop, and protecting us from pathogenic bacteria. These are what are often known as the "good" bacteria: a diverse set of beneficial species that improve our health and wellbeing.'

These bacteria perform many important functions for us, and if the wrong species take hold inside us the results can be dramatic. An upset stomach is a common result of a pathogen such as Salmonella taking hold, but there are also many other effects of having undesirable bacterial species in the gut. These include chronic inflammatory bowel diseases such as Crohn's disease or ulcerative colitis, and an increased risk of conditions such as heart disease and diabetes. There has also been some suggestion that the microbiota contributes to some psychological disorders.

Discussing the latest study, co-lead author Jonas Schluter of Memorial Sloan Kettering Cancer Center - who has carried out previous work on the 'stickiness' of bacteria - said: 'Our gut is lined with our own epithelial cells, and we use these to secrete all kinds of compounds into the gut. That is, we don't just absorb nutrients from our gut, we release a lot of things back in. This includes mucus, which can be modified so that it sticks to particular bacteria and also antibodies - one of the key tools of the immune system.

'In particular, a class of antibody called IgA (immunoglobulin A) is released into the gut in large quantities. This is a sticky molecule that comes in a vast number of forms where each one can preferentially target a particular strain or species of bacteria. By using things like mucus and IgA, therefore, humans have the ability to make certain bacteria sticky. We are proposing that this can be used to hold them close to the epithelial surface in the gut.'

Senior author Professor Kevin Foster of Oxford University added: 'Our study is based on a computational model of the gut and the key next step is a direct empirical test of our idea. However, as we discuss in our study, existing data do support our idea that stickiness may be a simple and powerful way to control the bacteria that we carry with us.'
-end-


University of Oxford

Related Immune System Articles:

Immune system upgrade
Theoretically, our immune system could detect and kill cancer cells.
Using the immune system as a defence against cancer
Research published today in the British Journal of Cancer has found that a naturally occurring molecule and a component of the immune system that can successfully target and kill cancer cells, can also encourage immunity against cancer resurgence.
First impressions go a long way in the immune system
An algorithm that predicts the immune response to a pathogen could lead to early diagnosis for such diseases as tuberculosis
Filming how our immune system kill bacteria
To kill bacteria in the blood, our immune system relies on nanomachines that can open deadly holes in their targets.
Putting the break on our immune system's response
Researchers have discovered how a tiny molecule known as miR-132 acts as a 'handbrake' on our immune system -- helping us fight infection.
Decoding the human immune system
For the first time ever, researchers are comprehensively sequencing the human immune system, which is billions of times larger than the human genome.
Masterswitch discovered in body's immune system
Scientists have discovered a critical part of the body's immune system with potentially major implications for the treatment of some of the most devastating diseases affecting humans.
How a fungus can cripple the immune system
An international research team led by Professor Oliver Werz of Friedrich Schiller University, Jena, has now discovered how the fungus knocks out the immune defenses, enabling a potentially fatal fungal infection to develop.
How the immune system protects us against bowel cancer
Researchers from Charité - Universitätsmedizin Berlin have discovered a protective mechanism which is used by the body to protect intestinal stem cells from turning cancerous.
How herpesviruses shape the immune system
DZIF scientists at the Helmholtz Zentrum München have developed an analytic method that can very precisely detect viral infections using immune responses.
More Immune System News and Immune System Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#542 Climate Doomsday
Have you heard? Climate change. We did it. And it's bad. It's going to be worse. We are already suffering the effects of it in many ways. How should we TALK about the dangers we are facing, though? Should we get people good and scared? Or give them hope? Or both? Host Bethany Brookshire talks with David Wallace-Wells and Sheril Kirschenbaum to find out. This episode is hosted by Bethany Brookshire, science writer from Science News. Related links: Why Climate Disasters Might Not Boost Public Engagement on Climate Change on The New York Times by Andrew Revkin The other kind...
Now Playing: Radiolab

An Announcement from Radiolab