Medical News Today: How does the immune system know friend from foe in gut bacteria?

Microorganisms in the human digestive tract are necessary for proper nutrition, metabolism and immune functioning. However, because the human body has mechanisms to destroy pathogens, cooperating scientists in Germany and Italy conducted research as to how the body differentiates between necessary micro-biotic organisms in the gut and detrimental invaders. They found that dendritic cells (DC) act as messengers that either repress immune responses, or promote these responses. When DC are functioning properly, they deliver protein-encoded messages to the immune system that certain types of microorganisms found in the gut are desirable, thus not to be destroyed. However, if DC cease carrying this message, the body will treat the friendly gut microbiota as pathenogenic, causing a number of undesirable symptoms in the human host.

Key Takeaways:

• The digestive system contains trillions of bacteria, most of them needed to maintain digestion and healthy body functions.
• The body's immune response is to attack bacteria that should not be in your body.
• Amazingly the body manages to tell apart the good and bad bacteria through dendritic cell response.

"a type of cell called dendritic cells (DCs) that have evolved two distinctive - and what may appear to be opposite - roles in the human body, in that they can both promote and inhibit immune response."

Read more: //www.medicalnewstoday.com/articles/316335.php