Neuroimmunology of Host-Microbial Interactions
The study of the effects of neuroendocrine-immune interactions on microbial pathogenesis and immunity during the course of an infectious disease has emerged as a new interdisciplinary research area, termed psychoneuroimmunology. Neuroendocrine control of a wide range of immune responses occurs via a host of neuropeptides and neurohormones. The interaction of the neuroendocrine factors and their receptors on immunocompetent cells could alter the cellular activity through the activation of second messengers including cAMP and cGMP. Stress studies on immune function have led many to believe that adrenal glucocorticoids are the only stress induced biological modifiers of immune response. In contrast to the differential effect of hypothalamus-pituitary-adrenal (HPA) axis activation on mycobacterial growth, activation of the HPA axis suppressed the anti-microbial mechanisms of macrophages from both the Mycobacterium bovis (BCG) susceptible and BCG resistant mice.