The brain’s immune system has been extensively utilized in many clinical practices to treat detrimental brain tumors, which are otherwise very difficult to deal with. For example, scientists utilize brain tumor cells that are extracted from patients to activate their dendritic cells (antigen-presenting cells), which are then used to ‘train’ T cells to enter the brain and attack and kill already existing tumor cells. This technique has shown promising results in many clinical setups. Taken together, neuroimmunology related research works ultimately aim at deciphering the extent at which the immune system is involved in regulating complex neuronal circuits and, thereby, are of prime importance to look for effective new strategies to treat disorders of the central nervous system.