Cross-talk between the nervous system and the immune system is increasingly appreciated. It has long been established that a hypothalamus-pituitary-adrenal axis exerts a mainly suppressive effect on immune responses by promoting glucocorticoid hormone production. In our previous work, we showed that, for the first time, a brain-spleen circuit that positively regulates plasma cell formation and antibody response. Importantly, this circuit place B cell immunity under direct control of brain activity, rendering it amenable to behavioral modulation. We are currently extending these studies to delineate the immune cell interaction map that translates neuronal commands to immunological outcomes, and decipher more neuronal circuitries that translates different stress signals into diverse immune outcomes. We are additionally interested in understanding how microglia, a resident immune cell type of the central nervous system, regulates neuronal cell states and functions under both physiological and pathological conditions.