Mechanisms underlying chemical sympathectomy-induced suppression of herpes simplex virus-specific cytotoxic T lymphocyte activation and function

Abstract

Lymphoid tissues are extensively innervated by noradrenergic fibers of the sympathetic nervous system. 6-hydroxydopamine (6-OHDA)-induced chemical sympathectomy is commonly used to assess the impact of this innervation on immune function. Using the glucocorticoid receptor antagonist RU486, the mineralocorticoid receptor antagonist spironolactone, and the β-adrenergic receptor antagonist nadolol, the roles of corticosterone and norepinephrine in sympathectomy-mediated modulation of both the primary and memory cellular immune responses to herpes simplex virus type 1 (HSV-1) infection was investigated. We demonstrated that both of these immunomodulators play a role in mediating sympathectomy-induced suppression of the generation of HSV-specific primary cytotoxic T lymphocytes (CTL) and the activation of HSV-specific memory CTL (CTLm). Furthermore, we demonstrated a role for both Type I and Type II corticosteroid receptors in the regulation of HSV-specific immunity. Overall, these findings not only further support a role for neuroendocrine-mediated modulation of immune function, but also a need to exercise caution in attributing the effects of chemical sympathectomy to solely the absence of sympathetic innervation of lymphoid tissues.