Central administration of prostaglandin E2 suppresses in vitro cellular immune responses

S. Rassnick, D. Zhou and B. S. Rabin Department of Neuroscience, University of Pittsburgh School of Medicine, Pennsylvania 15213-2582, USA. Research suggests that the regulation of the function of the immune system by the central nervous system (CNS) involves the integrative responses of multiple neural systems that affect neuroendocrine and sympathetic nervous systems. To determine whether prostaglandin E2 (PGE2) is involved in the modulatory mechanisms of immune system function, it was administered intracerebroventricularly (ICV) to conscious male rats. One hour later, spleen and peripheral blood lymphocytes were collected for culture with nonspecific mitogens. ICV administration of PGE2 decreased blood lymphocyte proliferative responses to the T-cell mitogens phytohemagglutinin and concanavalin A and decreased spleen lymphocyte proliferative responses to phytohemagglutinin and lipopolysaccharide (a B-lymphocyte mitogen). ICV administered PGE2 also stimulated the activity of the hypothalamic-pituitary-adrenal axis, as reflected by increased plasma concentrations of adrenocorticotropic hormone and corticosterone. Thus PGE2 may act in the CNS as a hormonal modulator of immune system function.