Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Understanding How Lymph Nodes Respond to Infection May Redefine How Immune System Functions

20.11.2003


Duke University Medical Center researchers may have solved the mystery of why lymph nodes swell when the body fights infection. Their findings may redefine how the immune system functions, they said.

Their research, published in the December 2003 issue of Nature Immunology, centered on the role of mast cells. Mast cells are immune cells that are typically found just under the skin and in the lining of the intestine and lungs and were previously associated primarily with the induction of allergic reactions. The Duke researchers report that allergic reactions are only a side effect of mast cells’ much more important role as a regulator of the body’s immune system.

"Mast cells serve as the command post for the immune system during infections," said Soman Abraham, Ph.D., professor of pathology, associate professor of immunology and senior author of the paper. "White blood cells are sequestered within these nodes and, following proper activation, they can specifically target infectious agents and aid the host in clearing unwanted pathogens."



Abraham said the discovery that mast cells can initiate the activation and swelling of nodes through release of specific signaling molecules points to the possible use of mast cell products for the development of vaccines designed to boost the potency of the immune response.

"Mast cells have been much maligned because of their contribution to many diseases including asthma, arthritis, Crohn’s disease and multiple sclerosis," said Abraham. "Our research shows that mast cells play an important role in immune surveillance and defense against infectious agents."

The human immune system comprises two components that protect it against invading pathogens. The first line of defense is the innate immune system, a quick-acting response triggered immediately when a pathogen enters the body. The innate immune response responds the same regardless of the pathogen and attacks the pathogen for the first several days until the adaptive immune response can begin its attack.

The adaptive immune system is tailored specifically to the pathogen it is attacking. Once the immune system identifies an invader, draining lymph nodes recruit infection-fighting T-cells within 24 hours. During the next week or so, the T-cells proliferate and induce B-cells to produce antibodies specific to the invader. The result is swollen lymph nodes, which are the first discernable sign that the adaptive immune system is in effect.

Previous studies by Abraham showed that mast cells trigger the body’s innate immune system by releasing a molecule called tumor necrosis factor (TNF) and recruiting infection-clearing cells called neutrophils. However, the role of mast cells in the adaptive immune system remained unknown.

To examine the role of mast cells in the adaptive immune system, the Duke researchers studied the lymph nodes of mast cell-deficient mice. When the scientists introduced bacteria into the animals, their lymph nodes did not swell. However, when the mice were injected with mast cells, their nodes did swell. Further, specific activation of mast cells in the skin induced a rapid increase in TNF in the lymph nodes and recruitment of T cells.

"We are showing that the mast cells are critically involved in both the innate and adaptive immune systems," said Abraham. "Both are triggered with the release of TNF by the mast cells. The innate immune system, through TNF and neutrophils, attack the pathogen first, but within hours, TNF has reached the lymph nodes, triggering the adaptive immune system. Infection fighting T-cells are recruited and a specific attack on the pathogen begins. Within days, the body is producing antibodies and fighting back."

The involvement of mast cells in the adaptive response is a major shift in the understanding of the immune system and its function, said Salvatore Pizzo, M.D., Ph.D., chairman of the department of pathology and a member of the research team.

"When you pick up a textbook two years from now that shows how the immune system functions and the way a node responds to an infectious agent, you are going to see a whole new pathway," said Pizzo. "Mast cells are much more than just bad actors making you feel sick when you are exposed to noxious agents. They are actually major players helping you deal with these noxious agents."

"With a clearer understanding of the adaptive immune system and the role of mast cells, comes the opportunity for new therapeutics that could improve disease protection," said Abraham.

"It’s been known, particularly with allergy and asthma, that mast cells are involved in immune dysfunction," he said. "But their real physiological role is triggering both the innate and adaptive immune systems. Future research needs to focus on this role. We need to continue to dissect the process and adapt some of it to improve immunity and disease protection."

The National Institutes of Health and the Sandler Foundation for Asthma Research funded the research. Co-authors of the paper include James B. McLachlan; Justin P. Hart, Ph.D.; Christopher P. Shelburne, Ph.D.; Herman F. Staats, Ph.D.; and Michael D. Gunn, M.D., all of Duke University Medical Center.

Amy Austell | dukemed news
Further information:
http://dukemednews.org/news/article.php?id=7208

More articles from Life Sciences:

nachricht Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University

nachricht Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>