Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Immune cells in the liver take a ride

05.04.2005


Scientists at New York University School of Medicine viewing the actual journey of immune cells in the liver have found that these cells travel in the liver’s blood vessels with surprising speed and agility.



It is the first time that the movement of live immune cells called natural killer T (NKT) cells has been seen in the liver, according to a study published in the April 5, 2005, issue of the Public Library of Science, an open-access, online journal.

NKT cells are the guardians of the liver. They patrol the liver for foreign molecules on bacteria and viruses and once they find the interlopers, they alert the immune system to their presence. They are also thought to play a role in disposing of damaged cells, and in scouting for tumors.


Led by Dan R. Littman, M.D., PhD., professor of pathology and a Howard Hughes Medical Institute Investigator, and Michael L. Dustin, Ph.D., associate professor of pathology, the study analyzed over a period of hours the movement of NKT cells and their response to foreign protein, or antigen, in mice.

The study revealed a number of surprises. First, the NKT cells did their work almost entirely within the blood vessels of the liver. Previously, conventional theory held that these cells were forced from the blood into the tissues, where they did their specialized work. "This is the first example of a system in which a cell’s surveillance for antigen is intravascular rather than within a tissue," says Dr. Littman.

Second, the NKT cells appeared to have the agility of a pro athlete. The cells moved and changed directions quickly, sometimes traveling against the direction of flowing blood, no mean feat.

The researchers were able to trace the movement of the cells, by replacing a gene called CXCR6 with a gene for green fluorescent protein, which glows and makes the cells visible under a microscope. The researchers used a technique called intravital fluorescence microscope imaging to observe the behavior of the glowing cells in live mice.

The study showed that the cells were undisturbed by the rapid blood flow, latching on to the vessels, then moving in random patterns in search of infected cells. "Despite the force of the directional blood flow, the cells were able to hold their own, moving and changing direction, sometimes passing each other within a single blood vessel," explains Dr. Dustin.

In another part of the study, the researchers injected a foreign molecule. Here again, the cells behaved like athletes. They abruptly stopped and remained still, signaling that they had found the antigen and were ready to undertake their next task of alerting the immune system.

And there was yet another surprise. Drs. Littman and Dustin had expected that replacing the CXCR6 gene would directly affect the movement of the NKT cells. The CXCR6 gene encodes a receptor molecule on the surface of cells that is involved in cell movement and attraction. Replacement of the gene, which renders the cells receptor-deficient, should inhibit their ability to cling to the vessels, thereby directly inhibiting their movement.

But the researchers found that the replacement of the gene did not affect the movement of NTK cells, they hung on and patrolled for invaders just as well as cells with the gene. However, their survival rate was reduced, leading the scientists to surmise that the gene was somehow involved directly in a survival mechanism.

Dr. Littman explains the experiments so far have been artificial because the antigen was injected. The next step is to determine the kinds of pathological situations in which the cells become activated.

Dr. Dustin says his laboratory now is investigating a mouse model for liver fibrosis, triggered by bile duct obstruction, to see how cells with CXCR6 move under various conditions. "There is also significant interest in studying the way in which NKT cells respond to antigen so that they might be used in tumor vaccines," he says.

Pamela McDonnell | EurekAlert!
Further information:
http://www.nyumc.org

More articles from Life Sciences:

nachricht Magic number colloidal clusters
13.12.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Record levels of mercury released by thawing permafrost in Canadian Arctic
13.12.2018 | University of Alberta

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Magic number colloidal clusters

13.12.2018 | Life Sciences

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>