Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Natural killer cells have a memory


Researchers at the University of Bonn and the Ludwig-Maximilians-Universität of Munich have decoded a new mechanism of how the immune system can specifically attack pigmented cells of the skin. It was previously believed that natural killer cells did not have an immunological memory for the body's own tissues. However, the scientists have now showed that these immune cells can indeed “remember” pigmented cells when they come into more frequent contact with a specific contact allergen. These results may provide new insights into the development of the disease vitiligo and may also offer new options for the treatment of malignant melanoma. These results have now been published in “Immunity”.

Pigmented cells of the skin are crucial as a protective shield against UV-radiation. An often-desired suntan can only form with the aid of the enzyme tyrosinase inside these pigmented cells. The more exposure to sunshine, the more pigments are formed by this enzyme.

Dr. Jasper van den Boorn, Prof. Dr. Gunther Hartmann and Prof. Dr. Veit Hornung in the lab of the Institute of Clinical Chemistry and Clinical Pharmacology at the University Hospital Bonn.

© Photo: Rolf Müller/Ukom UKB

The compound monobenzone can specifically block tyrosinase and thereby trigger a stress reaction. As a result, the immune system attacks the affected pigmented cells. A frequent consequence is vitiligo, which leads to milky-white unpigmented areas on the skin.

Scientific studies have shown that people with vitiligo are at lower risk of developing malignant melanoma. A possible method for treating this type of cancer could involve actively triggering vitiligo with the tyrosinase blocker monobenzone.

“The idea is to use a less severe disease as a weapon against malignant melanoma,” says Dr. Jasper van den Boorn from the Institute of Clinical Chemistry and Clinical Pharmacology of the University of Bonn, who previously researched this connection in his doctoral thesis at the University of Amsterdam and demonstrated the fundamental feasibility of this option.

Contact allergen must first be “activated”

“However, the initial mechanism by which the immune system identifies the monobenzone-exposed pigmented cells as dangerous, before attacking them, has been unclear so far," reports Prof. Dr. Veit Hornung, who recently moved from the University of Bonn to the Ludwig-Maximilians-Universität in Munich.

It is known that monobenzone has a contact-sensitizing effect on pigmented skin: In principle, this substance alone is inactive. Only when monobenzone docks onto the tyrosinase enzyme, a so-called hapten is generated in the pigmented cell. This is a newly formed “foreign structure” that can specifically activate the immune system. By applying low doses of monobenzone several times in succession on the rodents' skin the researchers explored this path in detail on mice.

The way in which the animals' immune defense reacted to this hapten amazed the researchers. “Normally the immune system mobilizes a mixture of various white blood cells to attack hapten-exposed tissues,” reports Dr. van den Boorn. “However, the multiple monobenzone exposures induced only natural killer cells to recognize and attack the pigmented cells." Natural killer cells are part of the innate immune system and kill abnormal cells - such as cancer cells or virus-infected cells. Previously, scientists believed that they did not have the capacity to remember and specifically attack the body's own tissues. Up to now, this phenomenon has only been attributed to T and B lymphocytes.

“However, our results clearly show that natural killer cells can also carry out a long-lasting and effective immune reaction against the body's own pigmented cells, including malignant melanoma cells,” says Prof. Dr. Gunther Hartmann, Director of the Institute of Clinical Chemistry and Clinical Pharmacology of the University of Bonn. The researchers established this by studying mice that were not able to form any functional T and B lymphocytes. Nonetheless, white spots still developed in the animals' fur, and previously transferred malignant melanoma cells were destroyed, because the mice’s natural killer cells remembered and attacked the pigmented cells.

The NLRP3 inflammasome serves as a checkpoint

In order for this immune response to occur, an immune-checkpoint had to give the green light first: the NLRP3 inflammasome. “This is a protein complex that integrates multiple pieces of signaling information in macrophages, special phagocytes that reside in tissues. Once switched on, macrophages then decide whether immune cells including natural killer cells receive their marching orders,” explains Prof. Dr. Veit Hornung. If the researchers incapacitated this checkpoint, the monobenzone-induced tyrosinase hapten did not trigger the desired immune reaction anymore.

The results may open up new therapeutic avenues for the treatment of malignant melanoma, demonstrate a new type of immune recognition and could even shed new light onto the incipient events causing the development of vitiligo.

Publication: Jasper G. van den Boorn, Christopher Jakobs, Christian Hagen, Marcel Renn, Rosalie M. Luiten, Cornelis J.M. Melief, Thomas Tüting, Natalio Garbi, Gunther Hartmann & Veit Hornung: Inflammasome-dependent induction of adaptive NK cell memory, Immunity, DOI: 10.1016/j.immuni.2016.05.008

Media contact information:

Dr. Jasper van den Boorn
Institute of Clinical Chemistry and Clinical Pharmacology
University of Bonn Hospital
Tel. ++49-228-28751143

Prof. Dr. Veit Hornung
Gene Center and Department of Biochemistry
Ludwig Maximilian University of Munich
Tel. ++49-89-2180711110

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:

More articles from Health and Medicine:

nachricht Advanced analysis of brain structure shape may track progression to Alzheimer's disease
26.10.2016 | Massachusetts General Hospital

nachricht Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>