STRESS-INDUCED CHANGES IN IMMUNE FUNCTION ARE ASSOCIATED WITH INCREASED PRODUCTION OF AN INTERLEUKIN-1-LIKE FACTOR IN YOUNG DOMESTIC-FOWL

Investigation of the effects of stress on the immune system in young d eveloping animals is hampered by many variables such as maternal inter actions and physical size of immune organs. Young, precocial domestic fowl were used to overcome these difficulties. Domestic fowl, 14 days posthatch, served as an animal model to investigate the effects of str ess (acute social isolation) on a rapidly developing immune system. Gr oup-housed animals were isolated for 30, 60, or 90 min and assayed for numerative and functional changes in immune parameters in spleen and blood. The socially isolated birds showed an increase in body temperat ure, indicative of stress. The number of leukocytes/ml of blood increa sed in a time-dependent fashion, but the number of leukocytes in the s pleen did not. The stress of isolation resulted in a significant incre ase in B-lymphocyte mitogen proliferation at 30 min, which decreased w ith time. Social stress also induced a time-dependent decrease in T-ly mphocyte mitogen proliferation, which was significant by 90 min. Assoc iated with changes in mitogen responsiveness was a significant increas e in the production of an IL-1-like factor by splenic adherent cells f rom animals isolated for 30 min, which decreased in a time-dependent m anner to return to baseline by 90 min. Thus, young domestic fowl repre sent a practical model for the examination of the effects of stress on immune function in a developing animal. (C) 1994 Academic Press, Inc.