IMPACT OF DIFFERENTIAL HOUSING ON HUMORAL IMMUNITY FOLLOWING EXPOSURETO AN ACUTE STRESSOR IN RATS

The purpose of this study was to examine the effect of differential ho using on humoral immunity following exposure to an acute stressor. For ty male Sprague-Dawley adult rats were randomly assigned to either a s ingly housed or group-housed (five rats/cage) condition. Approximately 2 weeks after the start of the study, all animals were immunized with 1 ml of a 10% suspension of sheep red blood cells (SRBC) in saline. A fter the injections, half of the animals from each housing condition w ere subjected to an acute stressor (forced swim, 60 min/day for 3-5 da ys). Animals exposed to the acute stressor displayed adrenal gland hyp ertrophy and reduced thymus and spleen weights compared to the unstres sed (control) animals. Both behavioral stimuli (housing and forced swi m) demonstrated no effect on antibody production to SRBC. However, sin gly housed animals showed an increase in lymphocyte percentage, and co rticosterone and glucose levels regardless of subsequent exposure to a cute stress. Within a treatment condition, there were no significant c orrelations between the immune and endocrine measures. It was conclude d that reduced social contact (i.e., individual housing) with subseque nt exposure to an acute stressor does not appear to inhibit immunologi cal responsiveness to an antigen.