Neuroendocrine factors alter host defense by modulating immune function

An increasing body of evidence demonstrates that there is bidirectional communication between the neuroendocrine and immune systems. Interaction between these systems results ill a variety of outcomes, including the well documented sickness behavior elicited by cytokines of the immune system that can enter the brain and activate second messengers that modify neuronal activity. Crosstalk between the neuroendocrine and immune systems call also result in production or factors by the nervous and endocrine systems that alter immune cell function and subsequent modulation of immune responses against infectious agents and other pathogens. Continued exposure to molecules produced by the neurcendocrine system has also been known to increase susceptibility and/or severity of disease. Furthermore, neuroendocrine factors are thought to play a major role in gender-specific differences in development of certain disorders, including autoimmune/inflammatory diseases that have it two to tenfold higher incidence in females compared to males. Necuroendocrine factors can affect immune cells at the level of gene transcription but have also been shown to modify immune cell activity by interacting with intracellular molecules, resulting in modified ability of these cells to mount a potent immune response. In this review, we will consider various effects of the neuroendocrine system and its proteins on specific populations of immune cells and associated responses in host immunity against pathogens. We will further discuss how this modification of immune cell activity by the neuroendocrine system can contribute to susceptibility/severity of disease development. Published by Elsevier Inc.