Scientists have found clues that show that certain cells of the immune system may play a role in addition to protecting against microbial invaders – protecting mental health.
In the study conducted by Yale, the cells of the immune system in the spinal fluid of MS patients and healthy subjects were compared.
The results support an emerging theory that gamma interferons, a type of immune cell that helps induce and modulate a variety of immune system responses, may also play a role in preventing depression in healthy people.
“We were surprised that normal spinal fluid would be so interesting,” said David Hafler, William S. and Lois Stiles Edgerly, a professor of neurology, professor of immunobiology and lead author of the study.
How was the discovery made?
Previous research has shown that blocking gamma interferons and the T cells they produce can cause depression-like symptoms in mice.
Hafler notes that depression is also a common side effect in MS patients treated with a different type of interferon.
Scientists have used a new technology which allows a detailed examination of individual cells.
With its help, the researchers were able to show that the T cells in the spine fluid of healthy people share similarities with those of patients with MS.
However, in healthy people, the cells lack the ability to replicate and cause harmful inflammation, a response seen in autoimmune diseases such as multiple sclerosis.
In essence, the immune system in everyone’s brain is ready to produce an inflammatory immune system response, but at the same time, it can have a function other than defending against pathogens, Hafler said.
“These T cells found in healthy people have another purpose there and we speculate that this is to help us maintain our mental health,” he said.
The researchers plan to explore more closely how the immune system’s responses to the central nervous system could affect psychiatric disorders, such as depression.