You are what you eat: Immune cells remember their first meal

May 20, 2016

Scientists at the University of Bristol have identified the trigger for immune cells' inflammatory response -- a discovery that may pave the way for new treatments for many human diseases.

Immune cells play essential roles in the maintenance and repair of our bodies. When we injure ourselves, immune cells mount a rapid inflammatory response to protect us against infection and help heal the damaged tissue.

Lead researcher Dr Helen Weavers, from the Faculty of Biomedical Sciences said: "While this immune response is beneficial for human health, many human diseases (including atheroscelerosis, cancer and arthritis) are caused or aggravated by an overzealous immune response. A greater understanding of what activates the immune response is therefore crucial for the design of novel therapies to treat these inflammatory disorders.

"Our study found that immune cells must first become 'activated' by eating a dying neighbouring cell before they are able to respond to wounds or infection. In this way, immune cells build a molecular memory of this meal, which shapes their inflammatory behaviour."

The team's research, published in the journal Cell, used the fruit fly (Drosophila melanogaster) to study how a particular immune cell (the macrophage) becomes activated in order to respond to injury or infection. Using the fly allowed researchers to make time-lapse movies of the dynamic behaviour of the immune cells as they migrate within a living organism. It also allowed them to easily manipulate different genes and signalling pathways within the fly, to test which genes are important for immune cell behaviour.

Using genetics, the researchers dissected the mechanism by which the molecular memory is generated within the immune cell. Ingestion of the dying cell activates signalling via a calcium flash, which leads to an increase in the amount of an important damage receptor Draper in the immune cell. High levels of this receptor enable the 'primed' immune cell to sense the damage signals that entice them towards a wound during inflammation. Without this priming, the cells are blind to wounds and infections.

Professor Paul Martin said: "Our work has important implications for human health, given that the pathology of many human diseases is often caused by an inappropriate inflammatory response. Understanding how one signal (in this case a dying cell) can influence the ability of an immune cell to respond to a subsequent signal is a major step towards finding novel ways to clinically manipulate immune cells away from sites of the body where they are causing the most damage."

Wellcome Trust Senior Research Fellow Professor Will Wood said: "Using flies to study human disease might seem at first glance to be a rather strange approach, but this is an exciting advance in our understanding of immune cell behaviour, and takes us a step closer to designing novel therapeutic ways to influence immune cell behaviour within patients in the clinic."
-end-
The study was a collaboration between the laboratories of Professor Paul Martin, from the Schools of Biochemistry and Physiology, Pharmacology and Neuroscience, and Professor Will Wood, from the School of Cellular and Molecular Medicine, and was supported by the Medical Research Council and the Wellcome Trust.

Paper: 'Corpse engulfment generates a molecular memory that primes the macrophage inflammatory response' by Helen Weavers, Iwan Evans, Paul Martin and Will Wood in Cell. -- http://www.cell.com/cell/fulltext/S0092-8674(16)30494-9

Photo: A high-resolution image is available to download from: https://fluff.bris.ac.uk/fluff/u1/sd15464/cRfFjr11WTeYwHkgl20LqAXQF/

Caption: A confocal image of immune cells (green and red) migrating through the 3-D space (blue) within a living Drosophila embryo.

Scribble Video:https://www.youtube.com/watch?v=IaHYwuCEnp4

University of Bristol

Related Immune Response Articles from Brightsurf:

Boosting chickens' own immune response could curb disease
Broiler chicken producers the world over are all too familiar with coccidiosis, a parasite-borne intestinal disease that stalls growth and winnows flocks.

Cells sacrifice themselves to boost immune response to viruses
Whether flu or coronavirus, it can take several days for the body to ramp up an effective response to a viral infection.

Children's immune response more effective against COVID-19
Children and adults exhibit distinct immune system responses to infection by the virus that causes COVID-19, a finding that helps explain why COVID-19 outcomes tend to be much worse in adults, researchers from Yale and Albert Einstein College of Medicine report Sept.

Which immune response could cause a vaccine against COVID-19?
Immune reactions caused by vaccination can help protect the organism, or sometimes may aggravate the condition.

Obesity may alter immune system response to COVID-19
Obesity may cause a hyperactive immune system response to COVID-19 infection that makes it difficult to fight off the virus, according to a new manuscript published in the Endocrine Society's journal, Endocrinology.

Immune response to Sars-Cov-2 following organ transplantation
Even patients with suppressed immune systems can achieve a strong immune response to Sars-Cov-2.

'Relaxed' T cells critical to immune response
Rice University researchers model the role of relaxation time as T cells bind to invaders or imposters, and how their ability to differentiate between the two triggers the body's immune system.

A novel mechanism that triggers a cellular immune response
Researchers at Baylor College of Medicine present comprehensive evidence that supports a novel trigger for a cell-mediated response and propose a mechanism for its action.

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.

Read More: Immune Response News and Immune Response Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.