In a First, T cells are Found in the Healthy Human Brain

The brain is shielded from many substances by the blood-brain barrier, but this shield is not impenetrable. There are immune cells in the brain called microglia that can respond to potential invaders in the brain, but there is a lot we don’t know about how the adaptive immune system, which can ‘remember’ previous infections and respond accordingly, functions in the brain. Scientists have now shown that there are cells of the adaptive immune system in the…