The Hypothalamo-Pituitary-Adrenal (HPA) axis is an important regulator for the body's stress response. As a primary stress responsive system, HPA-axis secretes various neurotransmitters, hormones, and cytokines, which regulates the immune system. Natural killer (NK) cell which is plays an important role in the innate immune response, is specially decreased their numbers and loose cytolytic activity in response to stress. However, the effect of HPA-axis secreted proteins on NK cell activity has not been defined. Herein, we studied the effect of adrenal secreted adiponectin on NK cell cytotoxicity. Adiponectin which is well-known metabolic control protein, plays important roles in various diseases, including hypertension, cardiovascular diseases, inflammatory disorders, and cancer.

Signal sequence trap was used to find stress novel secretory protein from HPA-axis. Selected adiponectin was treated mouse mature primary NK cells and then examined the effect of adiponectin to NK cell cytotoxicity and cytokine expression level.

We found that adiponectin which is secreted from adrenal gland, suppress IL-2 induced NK cell cytotoxicity. And also investigated cytolytic cytokines are suppressed by adiponectin.

These data suggest that adiponectin inhibites NK cell cytotoxicity via suppression of cytotoxicity related target gene.