How Bacteria Helps the Immune System

While some bacteria cause infections, most species are harmless or perform beneficial functions, such as aiding digestion. These beneficial bugs are called commensal bacteria.

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One of the most important functions of commensal bacteria is boosting the immune system. Studies by other researchers have found that mice raised in sterile, germ-free environments 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 re-emerge when conditions improve.) 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. B cells are one of the key components of the immune system. They produce antibodies that fight harmful viruses and bacteria.

The findings suggest the possibility that some day, bacterial spores could be used to treat people with weakened or undeveloped immune systems, such as newborns, the elderly and patients undergoing bone marrow transplants.

In cancer patients, bacterial spores perhaps could boost the immune system to fight tumors. However, Knight warned that it would take years of research and clinical trials to prove whether such treatments were safe and effective.

Source: ANI