Cell: Cd4 plus T cells are present in the brain and affect the maturation of the brain's immune "sentinel".

!---- Our brains are as specially protected as a highly fortified headquarters -- the blood-brain barrier prevents other biomolecules from entering.at the same time, a small number of white blood cells can interact with the blood-brain barrier to enter the cerebral vascular gap.that is, the brain may have its own immune system, Sentinel.microglia is a resident immune cell in the brain that provides an inherent immune response, inflammatory response, and tissue repair to tissue.in 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) cells.CD4-T cells are well known as effective media for autoimmune diseases in the nerve field, such as multiple sclerosis and narcolepsy., it plays an important role in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, stroke, and so on.Despite 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 brains., a team of interdisciplinary scientists led by the Babraham Institute in the UK and Professor Adrian Liston of the University of Leuven in Belgium began a journey of searching for answers., July 22, in a study published in the journal Cell, Adrian Liston and others found that there are CD4-T cells 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 Institute.they keep circulating in our bodies and into all our organs, which have proved to include the brain.specifically, the researchers discovered the presence of CD4-T cells in healthy mice and human brains using microscopy and single-cell sequencing techniques.CD4-T cells are relatively evenly distributed in the brain region and are close to small glial cells., the study also quantified the number of T-cells in mouse and human brain tissue., there are about 2,000 CD4-T cells in the brains of healthy adult mice, 150 of which are regulatory T cells.researchers evaluated healthy human brain tissue removed during temporal lobe surgery using flow cytomytosis and found that the levels of CD4-T cells were similar to those in mice. CD4 plus T cells were present in healthy mice and the human brain to study the specific function of CD4-T cells in the brain, and the researchers turned to MHC II gene knockout (KO) mice. the mice showed insufficient CD4-T cells in both the peripheral and brain. as 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. , or CD4-T, plays a role in the maturation of glial cells in the brain. observations found 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 of the cortex neurons increased. these results show that CD4 plus T cells mainly affect the function of mature small glial cells on synapses. , 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 between them," the researchers said. we found that gut bacteria modify white blood cells and then bring that information into the brain. This may be the way the gut microbiome affects the brain. " concluding, the 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 a new understanding of their role in a range of neurological diseases. .