HealthIssue: How bacteria Give a Boost

How bacteria give a boost 

to immune system

Washington: Loyola University Health System researchers have discovered how certain types of bacteria boost the immune system.

       Senior author Katherine l Knight, and colleagues report their discovery in  a featured article in the June 15, 2010, issue of the Journal of immunology. The human body is teeming with bacteria. In each person, there are about 10 times as many bacterial cells as human cells. Bacteria live on skin, in the respiratory tract and throughout the digestive tract. The digestive tract alone is home to between 500 and 1,000 bacterial species.

     While some bacteria cause infections, most species are harmless or perform beneficial functions, such as aiding digestion. These beneficial bugs are called commensal bacteria. One of the most important functions of commensal bacteria is boosting the immune system. Studies by other researchers have found ronments have poorly developed immune systems. But until now, scientists have not known the mechanism by which bacteria help the immune system.

     knight's lab studied the spores from rod shaped bacteria called Bacillus, found in the digestive tract. (A spore consists of the DNA of a bacterium, encased in a shell. Bacteria form spores during times of stress, and researchers found that when they exposed immune system cells called B Lymphocytes to bacterial spores, the B cells began dividing and reproducing. Researchers further found that molecules on the surfaces of the spores bound to molecules on the surfaces of B cells. This binding is what activated the B cells to divide and multiply.