The Role of the Bursa of Fabricius and Highly Dilute Bursin in Immunoneuroendocrine Interactions in the Chicken

A huge set of data, pertaining to Mammals namely, supports the existence of two-way communication between the immune and neuroendocrine systems. For example, glucocorticoids released by the adrenals are immunodepressive; in turn, immune products act at different levels of the hypothalamo-pituitary-adrenal axis (HPA) (for review see Lilly and Gann, 1992). Also, the chief pineal hormone melatonin (MLT) is immunostimulatory (Maestroni et al., 1989) whereas interferon-γ stimulates the release of MLT by cultured pineal glands (Withyachumnarkul et al., 1990). The concept that products of the immune system act on the neuroendocrine system was suggested by (1977), based on their observation that in rats, serum corticosterone (CORT) increases during the course of immune response. However, in Mammals, most studies working out immunoneuroendocrine interferences deal with the T immune component mainly, therefore neglecting the involvement of the B lymphoid compartment, because the latter is rather anatomically diffuse. Therefore, it appears experimentally difficult to identify specific B immune signal (s) endowed with neuroendocrine competence.