The Role of Interleukin 2 in the Immune Response of Incoming Feeder Cattle

Abstract

Current thinking on the etiology of many production diseases suggests that the homeostatic stress responses in the animal are important contributing factors to disease susceptibility. Solutions to the problems of production diseases will be found only when a better understanding of resistance and cellular messenger mechanisms is available to modify production methods. Significantly,  interleukin 2 (IL 2) has been shown to be involved in immune interferon regulation. Studies suggest that environmental and management stressors in feeder calves may lower immune reactions by altering IL 2 production or activitiy in vivo. Data from our in vitro studies indicate that cortisol at physiologically attainable concentrations lowers IL 2 production and that increasing concentrations of cortisol are correlated with both lower lymphocyte proliferative responses and lower IL 2 activity. The results of a recent experiment indicate that lymphocytes from calves injected with adrenocorticotropic hormone (ACTH), in addition to displaying lower lymphocyte proliferative responses, produce less IL 2 than salineinjected controls. These results lead us to believe that our hypothesis of stress-induced immune alterations via lymphokine regulation may be correct.