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 New technique unveils 'matrix' inside tissues and tumors
29.06.2017 | University of Copenhagen The Faculty of Health and Medical Sciences

nachricht Designed proteins to treat muscular dystrophy
29.06.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making Waves

Computer scientists use wave packet theory to develop realistic, detailed water wave simulations in real time. Their results will be presented at this year’s SIGGRAPH conference.

Think about the last time you were at a lake, river, or the ocean. Remember the ripples of the water, the waves crashing against the rocks, the wake following...

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Nanostructures taste the rainbow

29.06.2017 | Physics and Astronomy

New technique unveils 'matrix' inside tissues and tumors

29.06.2017 | Life Sciences

Cystic fibrosis alters the structure of mucus in airways

29.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>