Table I. Expression of some selected cytokines and their receptors on neurons and glial cells. Th, T helper cell; C, cytokine; R, receptor; IFN, interferon; TNF-α, tumor necrosis factor alpha; IL, interleukin; AIDS, acquired immune deficiency syndrome; CNS, central nervous system; HPA, hypothalamus-pituitary-adrenal; BBB, blood-brain barrier; ACTH, adrenocorticotropic hormone.

Cytokine	Th1/Th2 type	Immune activity	C and R expression on neurons	C and R expression on glial cells
IFN-α	Not exactly classifiable	Antiviral, antiparasitic, antiproliferative activities; standard therapy for hairy cell leukaemia, metastasising renal carcinoma, other tumors, AIDS-associated Kaposi sarcomas, and viral infections	C inducible	C, R
IFN-γ	Th1	Antiviral, antiparasitic, antiproliferative activities	R	C, R
TNF-α	Not exacty classifiable	Causes cytolysis and cytostasis of many tumor cell lines; prothrombotic; induces synthesis of prostaglandin E2; mediates cachexia in tumor patients; involved in septic shock	R	C, R
IL-1	Th1	Important mediator of inflammatory reactions; antiproliferative and cytocical activities on certain tumor cell types; stimulation of Th cells to secrete IL-2 and of B cells to produce immunoglobulins; enhances synthesis of prostaglandin E2; modulates the electrophysiological behavior of neurons; directly affects the CNS as an afferent signal modulating the release of a number of hormones; activates the HPA axis	C, R	C, R
IL-2	Th1	Proliferation of T cells and activated B cells; damages the BBB and the integrity of the endothelium of brain vessel; modulates the electrophysiological behavior of neurons	C, R	R
IL-4	Th2	Proliferation and differentiation of activated B cells; promotes clonal expansion of specific B cells	R?	R
IL-6	Mainly Th2	Extremely pleiotropic cytokine influencing antigen-specific immune responses and inflammatory reaction; stimulates synthesis of ACTH; hematopoietic	C, R	C, R
IL-10	Th2	Inhibits the synthesis of a number of cytokines such as IFN-γ and IL-2 in Th1 cells	C, R	C, R