The goal of this project is to develop a more detailed mechanistic understanding of neuroendocrine regulation of immune responses through the refinement and validation of novel flow cytometric assays for the assessment of glucocorticoid receptor expression and function (Aim 1). The novel assays will then be used to determine whether in vivo cortisol levels correlate with glucocorticoid receptor expression in immune cells (Aim 2). Lastly, these novel flow cytometry-based assays will be used to understand how mind-body interventions might 'reset' this important bi-directional communication between the neuroendocrine and immune system (Aim 3). This research will form the basis for a larger, more comprehensive investigation of the mechanisms by which mind-body intervention changes neuroendocrine signaling and immune system function.  A more complete understanding of neuroendocrine control of immune cell function is important for understanding the molecular mechanisms by which mind-body interventions affect immune function through modulation of neuroendocrine signaling. Mind-body interventions, such as meditation and yoga, may have important effects on the immune system in part through the effects of these interventions on stress hormone signaling pathways. Our understanding of the potential effects of these interventions on the immune system is limited however, by gaps in our knowledge of how changes in stress hormone levels potentially achieved by these interventions actually affect the immune system. The long-term goal of this application is to develop new assays necessary to study the mechanisms by which stress hormones control immune cell function and how mind-body interventions 'reset' this communication pathway.