These results add to mounting evidence suggesting that a type of immune cell, gamma interferons, may play a role in preventing depression in healthy people. Gamma interferons help to induce and modulate a variety of immune system responses in the body.
Previous research in mice has found that depression-like symptoms may develop by blocking gamma interferons and the T cells. David Hafler, a senior author of the study, noted that depression is also a common side effect in patients with MS treated with a different interferon type.
“We were surprised that normal spinal fluid would be so interesting,” said Hafler, referring to the findings that immune cells may play a role other than protecting against microbial invaders, and potentially protect mental health.
T Cell Replication
For the study, researchers used a powerful new technology that allows a detailed examination of individual cells, which allowed them to show that while the characteristics of T cells in the spinal fluid of healthy people share similarities with those of MS patients, they don’t have the ability to replicate and cause the damaging inflammatory response seen in autoimmune disease such as MS.
“In essence, the immune system in the brains of all people is poised to make an inflammatory immune system response and may have another function than defending against pathogens, Hafler said.
This research helps to confirm that T cells serve another purpose other than just protecting against microbial invaders. Hafler and his team plan to continue their research to explore how the central nervous system’s immune system responses might affect psychiatric disorders such as depression. With limited information about the cause of depression, this study offers a whole new perspective on the cause and effect of the role of T cells and mental health.