Neuropeptide Y (NPY) stimulates cytokine production from antigen-presenting cells, but inhibits it from T cells.
A stress hormone sends mixed signals to immune cells, according to a study on
page 1527. Wheway and colleagues show that neuropeptide Y (NPY) activates antigen-presenting cells (APCs) but shuts off T cells. If correctly sequenced, these activities would both turn on and then limit certain immune responses.NPY is an abundant neuropeptide that is released from sympathetic nerve endings. In the brain, NPY regulates physiological and emotional processes, including metabolism, heart rate, and depression. NPY is also produced by activated immune cells and has been shown to dampen cytokine production by macrophages and inhibit the killer activity of natural killer cells.
The effects of NPY on T cells, however, have been controversial. Treatment with NPY ameliorates autoimmune disease in a mouse model of multiple sclerosis, suggesting a suppressive effect...
