THE ROLE OF NEUROENDOCRINE-IMMUNE INTERACTIONS IN THE INITIATION OF HUMORAL IMMUNITY IN CHICKENS

The presence of neuroendocrine immune interaction in mammalian species has been studied extensively and has been established. However, such an interaction is not as well established in avian species. Furthermor e, the role of such an interaction in the initiation of humoral immuni ty is not well understood. Therefore, the present studies were conduct ed to determine mechanisms involved in the initiation of humoral immun ity in chickens. Cornell K-strain White Leghorn immature male chickens were used for all the experiments. Changes in hormonal and leukocyte profiles after antigen stimulation were studied. The ability of differ ent leukocytes to produce ACTH was also investigated. It was concluded that the first step in the initiation of humoral immunity after antig en exposure is the release of interleukin-1 by macrophages, which in t urn stimulates the production of CRF by hypothalamus and/or leukocytes . It is important to mention that CRF production could also be a direc t effect of antigen stimulation. The CRF will then stimulate ACTH prod uction by anterior pituitary and/or leukocytes. In addition, CRF will directly enhance lymphocyte activities in the spleen. Corticosteroid p roduction will be stimulated by ACTH and will cause redistribution of lymphocytes from circulation to secondary lymphoid organs such as the spleen for antigen processing and eventual production of antibodies ag ainst the invading antigens. Finally, both ACTH and corticosteroids wi ll later act in a negative feedback manner to regulate and control the process of antibody production by inhibiting lymphocyte activities an d/or reducing the responsiveness to different stimuli. (C) Elsevier Sc ience Inc. 1998