Nav: Home

Gut reaction: How immunity ramps up against incoming threats

January 29, 2020

A new study has revealed how the gut's protective mechanisms ramp up significantly with food intake, and at times of the day when mealtimes are anticipated based on regular eating habits.

Researchers from the Walter and Eliza Hall Institute found, in laboratory models, that eating sets off a hormonal 'chain reaction' in the gut.

Eating causes a hormone called VIP to kickstart the activity of immune cells in response to potentially incoming pathogens or 'bad' bacteria. The researchers also found that immunity increased at anticipated mealtimes indicating that maintaining regular eating patterns could be more important than previously thought.

With the rise in conditions associated with chronic inflammation in the gut, such as irritable bowel and Crohn's disease, a better understanding of the early protective mechanisms governing gut health could help researchers to develop prevention strategies against unwanted inflammation and disease.

The research, led by Professor Gabrielle Belz and Dr Cyril Seillet from the Walter and Eliza Hall Institute, was published in the journal Nature Immunology.

At a glance

Eating activates immune cells in the gut that protect against pathogens and preserve gut health.

Immunity in the gut also ramps up at regular mealtimes in anticipation of eating and a potentially increased risk of infection.

Understanding the complex interactions between eating, gut health and inflammation could aid in the development of prevention and treatment strategies for chronic inflammatory diseases.

Armed against invaders

So how does it work?

When food is consumed nerves in the intestine produce a hormone called vasoactive intestinal peptide (VIP) to 'switch on' a protective response in the gut.

Professor Belz said the team showed, for the first time, that food-induced activation of VIP in preclinical models was vital for a subset of immune cells called ILC3s to mount a protective response in the gut.

"Food intake 'switches on' VIP, which plays a critical role in alerting the gut's army of ILC3 immune cells. In response, ILC3s secrete interleukin-22 (IL-22), which swings into protective action to defend against pathogens and maintain tissue integrity.

"We also showed that a deficiency in VIP limits the production of IL-22, which in turn negatively impacts the immune system's ability to prevent unwanted inflammation," she said.

The researchers used advanced imaging techniques to identify the 'players' integral to protective immunity in the gut. Using a new imaging technique that makes tissue translucent, the researchers were able to capture high-resolution, 3D images of how VIP and ILC3 immune cells interact to protect the gut. Results showed their close proximity which confirmed their interdependence.

Regular meals key to gut health

The researchers also showed that 'circadian clock' genes could enable the gut to ramp up immunity in anticipation of regular mealtimes.

Dr Seillet said baseline gut immunity fluctuated throughout the day, based on circadian rhythms and an anticipatory response to regular eating patterns.

"We saw that gut immunity not only spikes with food intake. It also rises and falls due to inbuilt cellular machinery regulated by the circadian clock gene Bmal1, which appears to activate immune cells when eating is likely," Dr Seillet said.

"While more work needs to be done to better understand this anticipatory mechanism, the results are very interesting and could help to explain why disruptions to circadian rhythms and regular eating patterns could increase chronic inflammation in the gut."

Protective effect

Dr Seillet said a detailed knowledge about mechanisms for gut protection and tissue repair could be useful for preventing against early-stage gut inflammation, before full-blown disease occurred.

"The next steps of our research include gaining a molecular understanding of what properties of food are responsible for kickstarting the process of protective immunity," he said.

"For example, are there certain diets that drive a more protective response than others?"

The study was supported by the Victorian Government and the Australian National Health and Medical Research Council.

Walter and Eliza Hall Institute

Related Immune Cells Articles:

Immune cells sculpt circuits in the brain
Brain immune cells, called microglia, protect the brain from infection and inflammation.
How tumor cells evade the immune defense
Scientists are increasingly trying to use the body's own immune system to fight cancer.
How immune cells activate the killer mode
Freiburg researchers find missing link in immune response.
Breast cancer cells can reprogram immune cells to assist in metastasis
Johns Hopkins Kimmel Cancer Center investigators report they have uncovered a new mechanism by which invasive breast cancer cells evade the immune system to metastasize, or spread, to other areas of the body.
Breast cancer cells turn killer immune cells into allies
Researchers at Johns Hopkins University School of Medicine have discovered that breast cancer cells can alter the function of immune cells known as Natural killer (NK) cells so that instead of killing the cancer cells, they facilitate their spread to other parts of the body.
Engineered immune cells recognize, attack human and mouse solid-tumor cancer cells
CAR-T therapy has been used successfully in patients with blood cancers such as lymphoma and leukemia.
Mapping immune cells in brain tumors
It is not always possible to completely remove malignant brain tumors by surgery so that further treatment is necessary.
Nutrient deficiency in tumor cells attracts cells that suppress the immune system
A study led by IDIBELL researchers and published this week in the American journal PNAS shows that, by depriving tumor cells of glucose, they release a large number of signaling molecules.
Experience matters for immune cells
The discovery that immune T cells have a spectrum of responsiveness could shed light on how our immune system responds to infections and cancer, and what goes wrong in immune diseases.
Immune cells against Alzheimer's?
German researchers have developed a novel, experimental approach against Alzheimer's.
More Immune Cells News and Immune Cells Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

How to Win Friends and Influence Baboons
Baboon troops. We all know they're hierarchical. There's the big brutish alpha male who rules with a hairy iron fist, and then there's everybody else. Which is what Meg Crofoot thought too, before she used GPS collars to track the movements of a troop of baboons for a whole month. What she and her team learned from this data gave them a whole new understanding of baboon troop dynamics, and, moment to moment, who really has the power.  This episode was reported and produced by Annie McEwen. Support Radiolab by becoming a member today at