Mystery to the origin of long-lived, skin-deep immune cells uncovered

June 7, 2012

Scientists at A*STAR’s Singapore Immunology Network (SIgN) uncovered the origin of a group of skin-deep immune cells that act as the first line of defence against harmful germs and skin infections. SIgN scientists discovered that these sentry cells of the skin, called the Langerhans cells (LCs), originate from two distinct embryonic sites - the early yolk sac and the foetal liver.

LCs are dendritic cells (DCs) found in the outermost layer of the skin. DCs are a critical component of the immune system because they are the only cells able to ‘see’ and ‘alert’ other responding to initiate a protective response against harmful foreign invaders. Like sentries of the immune system, DCs are strategically positioned where they are likely to encounter harmful pathogens. Identifying the source of these specialised immune cells may hold exciting possibilities to novel strategies for vaccination and treatment of autoimmune diseases and inflammatory skin disorders.

In contrast to other DCs which are constantly replaced by a circulating pool of bone marrow-derived precursors, LCs has the interesting ability to maintain themselves throughout life. While it is established that these long-lived sentry cells of the skin arise from precursors that are recruited to the skin prior to birth, this is the first time that the exact origin of the precursors of LCs is revealed through advanced fate-mapping technique (a method of tracing cell lineages to their embryonic origin).

In this study, published in the June issue of Journal of Experimental Medicine, Dr. Florent Ginhoux, and his team demonstrated that adult LCs originate from two distinct embryonic lineages in two succeeding waves. The first wave of precursor cells from the yolk sac ‘seed’ the skin before the onset of the foetal liver. Interestingly, the team discovered that at the later stage of development, the yolk-sac precursors are largely replaced by a type of white blood cells from the foetal liver.

Said Dr. Ginhoux, Principal Investigator of SIgN, “Whether this unique dual origin of Langerhans cells influences their ability to maintain skin integrity or dictate their specialised immune functions in response to microbes and vaccines needs to be examined. But having identified their origin surely opens new possibilities of using them as novel vaccination strategies or as therapeutic tool for treating inflammatory skin diseases like psoriasis.”

Scientific Director of SIgN, Professor Paola Castagnoli said, “This discovery sheds light on understanding the complexities of the immune system, in particular the relationship between immune responses and human diseases. It will bring us closer to our goal of discovering novel ways of treating and preventing a range of immune diseases that will impact healthcare.”

Explore further: Double duty: Versatile immune cells play dual roles in human skin

More information: The research findings described in this media release can be found in the 7 May online issue of The Journal of Experimental Medicine under the title, "Adult Langerhans cells derive predominantly from embryonic fetal liver monocytes with a minor contribution of yolk sac-derived macrophages” by Guillaume Hoeffel, et al. jem.rupress.org/content/early/ … 20120340.short?rss=1

Related Stories

Double duty: Versatile immune cells play dual roles in human skin

May 3, 2012
A new study helps to resolve an ongoing controversy about whether Langerhans cells (LCs) in human skin function to suppress the immune response and promote tolerance to normal human skin and its "friendly" microbial flora ...

Skin sentry cells promote distinct immune responses

July 21, 2011
A new study reveals that just as different soldiers in the field have different jobs, subsets of a type of immune cell that polices the barriers of the body can promote unique and opposite immune responses against the same ...

New path of origin for macrophages

May 2, 2012
Macrophages play a key role in the immune response, protecting organisms against infection and regulating the development of inflammation in tissue. Macrophages differ depending on where they are located and which tasks they ...

Scientists discover immune peacekeepers

October 17, 2011
There are more bacteria living on our skin and in our gut than cells in our body. We need them. But until now no-one knew how the immune system could tell that these bacteria are harmless.

Gatekeeper signal controls skin inflammation

January 26, 2012
A new study unravels key signals that regulate protective and sometimes pathological inflammation of the skin. The research, published online on January 26th in the journal Immunity by Cell Press, identifies a "gatekeeper" ...

Recommended for you

The skinny on lipid immunology

October 20, 2017
Phospholipids - fat molecules that form the membranes found around cells - make up almost half of the dry weight of cells, but when it comes to autoimmune diseases, their role has largely been overlooked. Recent research ...

Bacterial pathogens outwit host immune defences via stealth mechanisms

October 20, 2017
Despite their relatively small genome in comparison to other bacteria, mycoplasmas can cause persistent and often difficult-to-treat infections in humans and animals. An extensive study by researchers from Vetmeduni Vienna ...

Scientists find where HIV 'hides' to evade detection by the immune system

October 19, 2017
In a decades-long game of hide and seek, scientists from Sydney's Westmead Institute for Medical Research have confirmed for the very first time the specific immune memory T-cells where infectious HIV 'hides' in the human ...

Tracing cell death pathway points to drug targets for brain damage, kidney injury, asthma

October 19, 2017
University of Pittsburgh scientists are unlocking the complexities of a recently discovered cell death process that plays a key role in health and disease, and new findings link their discovery to asthma, kidney injury and ...

Researchers release the brakes on the immune system

October 18, 2017
Many tumors possess mechanisms to avoid destruction by the immune system. For instance, they misuse the natural "brakes" in the immune defense mechanism that normally prevent an excessive immune response. Researchers at the ...

How cytoplasmic DNA triggers inflammation in human cells

October 17, 2017
A team led by LMU's Veit Hornung has elucidated the mechanism by which human cells induce inflammation upon detection of cytoplasmic DNA. Notably, the signal network involved differs from that used in the same context in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.