ABSTRACT
Concepts and facts concerning immune-neuroendocrine interactions are discussed. The immune response elicits endocrine, autonomic, and brain functional changes. These changes can be mediated by soluble factors released by activated immunologic cells. As a result of these immune-neuroendocrine interactions the content of powerful agents such as hormones, neurotransmitters, and neuropeptides in the microenvironment of immunologic cells is modified. This leads to external immunoregulatory signals imposed upon autoregulatory mechanisms.
Subject(s)
Endocrine Glands/physiology , Immunity , Sympathetic Nervous System/physiology , Adrenal Cortex/physiology , Animals , Cell Communication , Glucocorticoids/physiology , Humans , Hypothalamo-Hypophyseal System/physiology , Hypothalamus/physiology , Lymphoid Tissue/innervation , Pituitary-Adrenal System/physiologyABSTRACT
The immune system is generally viewed as being regulated by a variety of mechanisms 'from within'. This internal regulation is conceived to be mediated by different subsets of T cells, by antibodies including their idiotypic determinants, monokines, yphokines, etc., which appear in a given sequence and quantity. This autoregulation confers a high degree of autonomy on the immune system. However, processes essentialfor thefunctioning of immunological cells, such as metabolism, transport of substances, allosteric changes in membranes, lymphoid cell proliferation and transformation, and lymphokine synthesis (for bibliography, see Ref. 1), are affected by several hormones and neurotransmitters. These facts constitute by themselves good arguments for another kind of regulation, one 'from without' (a term used by Medawar in 1973) which is, as Hugo Besedovsky, Adriana del Rey and Ernst Sorkin have proposed, superimposed upon and interwoven with autoregulation. This postulate requires the existence of information channels between the immune system and the central nervous system, i. e. that they should know about each other. The apparently lofty title of this presentation raises a number of critical questions about the workings of the immune system in its natural environment. Here the authors discuss these questions: What do immune cells know about the brain? What does the brain know about the immune system? How do the brain and the immune system communicate with each other? Are brain-immune system interactions linked in regulatory feedback circuits?
