New Study Shows How Viruses Use Unharmful Bacteria To Elude The Immune System
A new study, showed how certain viruses can evade the immune system using bacteria which are normally present in the human intestine. Sharon Kuss, study leader from the University of Texas, proved with this research how viruses can attach to molecules of bacteria (considered non-threatening by the immune system) to travel through the intestine. These molecules, which are components of the cell wall of bacteria (lipopolysaccharides), trigger the production of interleukin 10, a compound that transmits to the the immune system cells that the bacteria is not dangerous.
It is well known, that the mouth and the intestine are filled with bacteria and most of them do not represent a risk for health. Some of this bacteria even inhibit the growth of other types of bacteria, which are potentially harmful. The most populated part of the body populated with bacteria are the stomach and intestine, where bacteria helps in digestion and form vitamin K in the colon, vitamin which is needed for blood clotting and bone strengthening.
Between commensal bacteria and humans a symbiotic relationship is etablished from which both sides have onlyto gain (the bacteria receive nutrients, and humans are shielded from possible infection, benefiting in the same time from certain chemical compounds which are released by the bacteria metabolism).
To demonstrate how a virus uses a bacterium to elucidate the immune system, the researchers have injected large amounts of antibiotics in the intestine of experimental animals to kill all the present bacteria, then they tested animal’s susceptibility to viral infection. Researchers have shown that viruses are more able to cause an infection when they are using the bacteria from the intestine for transportation. Also, experimental animals that were born with sterile intestines are more resistant to viral infection. When the intestine was repopulated with bacteria, the susceptibility to viral infection has returned.
This study shows that there is still much to discover about the bacterial flora that lives inside us and about its relationship with external factors such as the polio virus. A course of antibiotics, which was considered until now harmless to viruses, could kill “the transporter”, and protect us from a possible infection in consequence.