Navigation Links
Specialized immune-system B cells play double-barreled role

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 m ouse 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 devel oped 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."


'"/>

Source:Duke University Medical Center


Related biology news :

1. Biologists Crack Genetic Code for Specialized Spider Silk
2. Fox Chase Cancer Center scientists identify immune-system mutation
3. Researchers in Montréal and the US create model of key immune-system component
4. New study may show how to forestall a fatal, virus-caused immune-system meltdown
5. Wisconsin scientists grow critical nerve cells
6. Spleen may be source of versatile stem cells
7. Researchers discover way to make cells in the eye sensitive to light
8. Priming embryonic stem cells to fulfill their promise
9. Lack of enzyme turns fat cells into fat burners
10. Poor prenatal nutrition permanently damages function of insulin-producing cells in the pancreas
11. Elusive HIV shape change revealed; Key clue to how virus infects cells
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/12/2017)... YORK , Jan. 12, 2017  New research undertaken ... the office of the future.  1,000 participants were simply asked ... three months which we may consider standard issue.  Insights on ... of 2017 were also gathered from futurists and industry leaders ... Dr. James Canton .  Some of ...
(Date:1/11/2017)... Intoxalock, a leading ignition interlock provider, has ... patent-pending calibration device. With this new technology, Intoxalock is ... data logs and process repairs at service center locations, ... drunk driving through the application of cutting-edge technologies is ... also for the customer who can get back on ...
(Date:1/6/2017)... Calif. , Jan. 6, 2017  Privately-held ... safety studies in healthy volunteers of a novel ... to treat acute pancreatitis. Acute ... typically a mild disorder, but can be very ... failure and sepsis, where extended hospital stays, time ...
Breaking Biology News(10 mins):
(Date:1/19/2017)... ... January 19, 2017 , ... ... software to leading biopharmaceutical and medical device manufacturers and regulators, is proud to ... CFR Part 11-compliant email client designed to provide product vigilance departments with the ...
(Date:1/19/2017)... ... January 18, 2017 , ... ... innovators, engineers, and scientists from around the world, was today awarded the "Best ... program is based entirely on merit and decided upon by a dedicated team ...
(Date:1/19/2017)... N.Y. , Jan. 18, 2017 Acupath ... services, announces the formation of an Executive Committee that ... and beyond. John Cucci , a ... promoted from Director of Business Development to Chief ... 2015, Mr. Cucci served in senior sales leadership roles ...
(Date:1/18/2017)... , Jan. 18, 2017 Applied BioMath ... modeling to drug research and development, today announced ... President, and CEO of Applied BioMath, will present ... and Modeling (BAGIM) Meeting on Thursday January 19, ... Cambridge , MA.   Dr. Burke,s talk "Quantitative ...
Breaking Biology Technology: