Central administration of prostaglandin E₂ suppresses in vitro cellular immune responses

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.