The healthy brain has CD4 plus T cells and affects the maturation of the immune "sentinel" in the brain.

Microglia is a resident immune cell in the brain that provides an inherent immune response, inflammatory response, and tissue repair to tissuesIn addition to small glial cells, healthy brains should also contain macrophages and dendritic cells around blood vessels, as well as detectable T-cells, B-cells, and natural killer (NK) cellsCD4-T cells are well known as effective media for autoimmune diseases such as multiple sclerosis and narcolepsy in the neurological fieldIn addition, it plays an important role in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, stroke, etcDespite the growing emphasis on the role of CD4-T cells in neuro-inflammatory and neurodegenerative diseases, there has been debate about the existence and potential function of CD4-T cells in healthy brainsTo that end, an interdisciplinary team of scientists led by the Babraham Institute in the UK and Professor Adrian Liston of the University of Leuven in Belgium began a journey to find outIn a July 22 study published in the journal Cell, Adrian Liston and others found that CD4-T cells do exist in healthy brains that affect the maturation of small glial cells"The misunderstanding of white blood cells comes from their names," explains Dr Oliver Burton of the Babraham InstituteThey keep circulating in our bodies and enter all our organs, which turn out to include the brainSpecifically, the researchers discovered the presence of CD4-T cells in healthy mice and human brains, including microscopy and single-cell sequencingCD4-T cells are relatively evenly distributed in the brain region and are close to small glial cellsThe study also quantified the number of T-cells in mouse and human brain tissueOf these, there were about 2,000 CD4-T cells in the brains of healthy adult mice, 150 of which were regulatory T cellsThe researchers evaluated healthy human brain tissue removed during temporal lobe surgery through flow cytomycin and found that the levels of CD4-T cells were similar to those in miceCD4-plus T cells are present in healthy mice and the human brain To study the specific function of CD4-T cells in the brain, the researchers turned to MHC II gene knockout (KO) miceThese mice showed insufficient CD4-T cells in both the peripheral and brainAs an interface between the nervous system and the immune system, they studied the effects of CD4-T cell deficiency on the composition of small glial cells results showed that when the mice lacked CD4-T cells in their brains, the small glial cells that should have acted as immune cells in the brain did not fully develop That is, CD4 plus T plays a role in the development and maturation of small glial cells in the brain Observations showed that the shape and number of small glial cells in mice lacking CD4-T cells did not appear to change significantly, but the key function of mature small glial cells- synaptic shear was disturbed and the synaptic density of the dermis in the cortex vertebral neurons increased These results show that CD4-T cells mainly affect the function of mature small glial cells on synapses In addition, the study found links between the gut microbiome "There are multiple links between bacteria in the gut and different neurological diseases, but there is no convincing explanation for the link," the researchers said We found that gut bacteria modify white blood cells and then bring this information into the brain This may be the way in which the gut microbiome affects the brain In summary, these findings open up a new set of questions about how the brain interacts with the immune system These results help to raise awareness of the role of immune cells in the brain and provide new insights into their role in a range of neurological diseases Source: Microglia Require CD4 T Cells to Complete the The Fetal-To-Adult Transition s2 White Blood Cells and their role in the brain of the brain Cell: There are CD4 plus T cells in the healthy brain that affect the maturation of the immune "sentinel" in the brain.