Nav: Home

Immune response depends on mathematics of narrow escapes

September 16, 2019

The way immune cells pick friends from foes can be described by a classic maths puzzle known as the "narrow escape problem".

That's a key finding arising from an international collaboration between biologists, immunologists and mathematicians, published in the journal Proceedings of the National Academy of Sciences.

The narrow escape problem is a framework often applied in cellular biology. It posits randomly moving particles trapped in a space with only a tiny exit, and calculates the average time required for each one to escape.

"This is a new application for some familiar equations," says co-author Justin Tzou from Macquarie University's Department of Mathematics and Statistics.

Tzou worked with colleagues at the universities of Oxford and Cambridge in the UK, the University of British Columbia in Canada, and the University of Skövde in Sweden to analyse how potential pathogens are probed by T cells, which identify and attack invaders. The researchers discovered that the equations used in the narrow escape problem play a key role in determining whether an immune response is triggered.

"The narrow escape problem turns out to be a close cousin of the situation with T cell receptors," Justin says. "It is about determining how long a diffusing particle remains in a certain region before escaping."

The unique shape of T cells creates what has been termed a "close-contact zone" for triggering molecules called T cell receptors. Unlike most cells, which have relatively smooth surfaces, T cells are covered in ruffles, bumps and other protrusions.

Scientists have known for a long time that T cell receptor molecules sit on the surface of the cells to recognise enemies and trigger a hostile response.

The receptors contain molecular patterns that mirror those found on the surfaces of bacteria, tumours, and other dangerous interlopers. But exactly how the process of recognition and triggering works - and particularly how it works so quickly and accurately - has been a mystery.

The researchers believe the unusually lumpy shape of the T cell plays a vital role.

The protrusions on the surface mean that its area of contact with a potential enemy cell is very small - only a couple of hundred nanometres across, or a thousand times smaller than the width of a human hair.

And according to the new theory, T cell receptors follow a two-second rule: if they spend more than two seconds in the small contact zone, a chemical process begins to sound the alarm and trigger an attack.

The size of the contact zone depends on the size of the bumps on the surface of the T cell.

"The smaller the zone, the less likely the T cell receptor is able to stay in that zone by chance, triggering an attack," Justin says. "It looks like the size of these protrusions keeps the process sensitive to the presence of the invader."

The researchers hope their work will provide new insights into immune deficiencies and auto-immune conditions, in which the immune system turns against the body's own cells.
-end-


Macquarie University

Related Immune Response Articles:

Platelets exacerbate immune response
Platelets not only play a key role in blood clotting, but can also significantly intensify inflammatory processes.
How to boost immune response to vaccines in older people
Identifying interventions that improve vaccine efficacy in older persons is vital to deliver healthy ageing for an ageing population.
Unveiling how lymph nodes regulate immune response
The Hippo pathway keeps lymph nodes' development healthy. If impaired, lymph nodes become full of fat cells or fibrosis develops.
Early immune response may improve cancer immunotherapies
Researchers report a new mechanism for detecting foreign material during early immune responses.
Researchers decode the immune response to Ebola vaccine
The vaccine rVSV-EBOV is currently used in the fight against Ebola virus.
Immune response depends on mathematics of narrow escapes
The way immune cells pick friends from foes can be described by a classic maths puzzle known as the 'narrow escape problem'.
Signature of an ineffective immune response to cancer revealed
Our immune system is programmed to destroy cancer cells. Sometimes it has trouble slowing disease progression because it doesn't act quickly or strongly enough.
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.
Having stressed out ancestors improves immune response to stress
Having ancestors who were frequently exposed to stressors can improve one's own immune response to stressors, according to Penn State researchers.
Researchers discovered new immune response regulators
The research groups of Academy Professor Riitta Lahesmaa and Research Director Laura Elo from Turku Centre for Biotechnology have discovered new proteins that regulate T cells in the human immune system.
More Immune Response News and Immune Response 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

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.