Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Specialized immune-system B cells play double-barreled role

27.07.2005


A specialized subpopulation of the antibody-producing B cells of the immune system plays a "double-barreled" role in triggering both kinds of immunity -- innate and acquired, Duke University Medical Center immunologists have discovered. The division of labor between B-1a and B-1b cells they have uncovered offers basic insights that could contribute to more rational development of vaccines, they said.



B cells are the arms factories of the immune system, producing antibodies that target invading microbes for destruction. Generally, B-1 cells have been thought to play a major role in the innate immune response -- the type of immunity that offers rapid, generalized responses to infections. Less understood has been any role in adaptive immunity -- in which the immune system develops a long-term immune response to an invader after vaccination or infection.

The researchers -- Karen Haas, Jonathan Poe, Douglas Steeber and Thomas Tedder -- published their findings in the July 2005 issue of the journal Immunity. The research was sponsored by the National Institutes of Health, the Arthritis Foundation, the Lymphoma Research Foundation and the Leukemia & Lymphoma Society.


The researchers studied a particular type of B cell called the B-1 cell. In contrast to the more conventional B-2 cells, B-1 cells have different distinguishing characteristics such as behavior, anatomical localization and types of antibodies produced. In contrast to well-studied B-2 cells, the cellular origins of B-1 cells and their subtypes remain unknown.

"The true function of B-1 cells in the body has been highly controversial over the past two decades," said Tedder. "They appear to be a primary defense mechanism for innate immunity in infections. In particular, however, the B-1b cells have been largely ignored because they’re present in relatively small numbers and are difficult to work with."

In the studies, Haas and her colleagues used two genetically altered mouse strains -- one that overproduced and one that was deficient in a protein called CD19 that is a key regulator of B-1a cell function and development. Thus, the two mouse strains enabled the researchers to explore the consequences of too many or too few B-1a cells. Also, the strain lacking CD19, and therefore B-1a cells, enabled the researchers to isolate sufficient numbers of pure B-1b cells for study.

The researchers studied how the immune systems of the two mouse strains reacted to infection with Streptococcus pneumoniae, the bacterium that causes pneumonia. They found that the mice lacking B-1a cells were susceptible to infection, showing they lacked the natural antibodies of the innate immune system. Yet, these mice could be protected by immunization, which activated their adaptive long-term immune system.

By contrast, the mice with overproduction of CD19 and thus overproduction of B-1a cells did not achieve adaptive immunity as a result of vaccination.

Thus, the researchers concluded that the B-1a cells regulate the innate immune response and the B-1b cells regulate the adaptive, long-term immune response.

Said Haas, "This reciprocal contribution of these two subtypes of B-1 cells to innate and acquired immunity was surprising to us. No one knew much about what these subsets do.

Our results indicate that there is a tiered response system in which one kind of B-1 cell consistently provides a low level of protection, while the other specifically responds to an infection to help eliminate it."

According to Haas and Tedder, the findings offer potential insights into the mechanism of vaccine action. For example, the new insights into the roles of the two B-1 cell subtypes could help explain why the immune-triggering molecules called antigens from the pneumococcus bacteria do not elicit a strong adaptive immune response in infants, people with compromised immune systems and the elderly. Such people may not have developed sufficient populations of B-1b cells to mount such an adaptive response.

According to Tedder, such basic insights as the new study yielded could be important for rational design of vaccines.

"Most vaccines are designed simply empirically," he said. "The designers develop a formulation that’s a best guess and test it on patients or animal models to determine its effectiveness. But now, research is reaching a point where we can understand the signals that switch certain B cell populations on and off and regulate their function.

"We certainly cannot say whether these particular findings about the role of these B-1 cell subtypes will directly impact on vaccine development," said Tedder. "However, understanding such key characteristics of the immune regulatory process will be critical to learning to successfully manipulate it with vaccines."

Dennis Meredith | EurekAlert!
Further information:
http://www.duke.edu

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>