A connection between CpG and the immune system
Scientists from the Medical College of Georgia have discovered that a component of DNA called CpG can both stimulate and suppress the immune system, depending on the dosage. This discovery could significantly improve cancer treatment procedures.
Scientists from Georgia have found that low levels of CpG increase inflammation, part of the body’s way of eliminating invaders. On the other hand, high doses block inflammation by increasing expression of the enzyme indoleamine-2,3-dioxygenase, or IDO, an immunosuppressor.
“The same therapy can have two different effects,” said Rusty Johnson, a M.D./Ph.D. student and one of the researchers. “It was assumed that giving this treatment at higher doses would cause more stimulation, but it has the opposite effect.”
Scientists hope that by “playing” with the dosage, they can come up with the most optimal one that would help in fighting tumors and harmful bacteria.
This group of scientists consulted their colleagues from the MCG’s Immunotherapy Center, and they have found out that IDO inhibits inflammation by blocking production of interleukin 6, a secreted factor that causes inflammation.
“This suggests that IDO is a counter-regulatory mechanism that serves as a balance to prevent too much inflammation,” said Johnson. “Too much inflammation leads to destruction of normal body tissue, and this shows IDO’s importance in preventing this from occurring.”
“We are already aware that IDO protects tumors from the immune system. But without it, a mouse becomes resistant to skin tumor formation, and tumors that do form are smaller and less malignant,” said Johnson.
The research was presented at the Midwinter Conference of Immunologists this month in Asilomar, California.
Source: mcg.edu
