Updating the complexity of T lymphocytes in the brain
T cells have an elaborate communication with almost all other cells. They are the main regulators of the immune system. But they also interact with the brain cells, the blood vessel cells and the cells in the lining of the intestine blue brain boost and the skin. Previous articles have described the communication with T cells and brain cells that are vital to maintain normal cognition and modify it during infections with “feeling of discomfort”, produced by a signal from T cells. It observed that T cells are involved in signals that stimulate the production of new neurons in the hippocampus. as part of the memory system. When depression occurs, these neurons decrease and the new stimulating neurons are correlated with treatments that improve depression.
Recently, a much greater amount of T cell activity has been found in the brain. A great variety of new cell types has been found. In addition, signaling has been found with other immune cells, such as antigen-presenting cells (APCs), but also other immune cells and glial cells. The new research is so fertile that the ramifications of all these new cells have just been discovered. There is a lot of important material that is still not understood. This message is an update of the complexity of T cells in the brain. There are many new types of immune cells that interact with T cells inside and outside the brain, causing effects on the brain. The current research is confusing but shows much more activity that will eventually become clear.
For a long time, it was thought that normally there were no immune cells in the brain. Then, the microglia were discovered as resident immune cells, then the existence of many T cells in the CSF. In recent years, the concept of “immune privilege” in the brain has changed. Microglia was in constant contact with T cells and other immune cells. But it was also discovered that there is usually a wide range of T cells in the brain that actively dialog with all brain cells, but also with all other immune cells. It is difficult to see a small cell in the vast brain, so it has been difficult to discover all types of T cells in the brain. Now, new research describes more T cell activity. Recently, lymphatic drainage of the brain has been described (see previous publication on compartments and brain barriers).
A wide range of new types of T cells in the brain
T cells in the brain prevent infections from microbes that have entered the brain, but they can also cause damage through inflammation and autoimmunity. Recently, memory cells have been found in the brain, as well as CD4 +, CD8 + and regulatory T cells.
Special molecules, used throughout the body to advertise microbes and damage T cells (MHC), are different in brain tissue. In addition, it is difficult for immune cells to cross the blood-brain barrier and enter the cerebrospinal fluid (see the article on brain barriers and microbes that cross barriers). Lymphatic drainage is different from other organs that alter the way T cells can function.
Unique T cells in the brain
Many types of T cells have special tasks in the periphery and a somewhat different function in the brain.
CD4 + T lymphocytes differentiate into several types of peripheral T lymphocytes with different receptors and signals of chemokines and integrins. Integrins and chemokines call Th (T helper) cells to various tissues. These can cause different types of brain tissue problems in various regions. Inflammation requires the arrival of special regulatory T cells to the brain: the T cells of the Forkhead P3 box (FOXP3) to the brain. FOXP3 has been described in previous publications as a way to stop food allergies, but it also helps reduce inflammation in the brain.