( ouse strains -- one that overproduced a...)Specialized immune-system B cells play double-barreled role

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
'"/>

Source:Duke University Medical Center

Page: 1 2 3
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