The effects of early life exposure to differential housing on adult immunocompetence in male and female Sprague-Dawley rats

The purpose of this study was to determine the influence of early life housing conditions on adult immunocompetence (antibody formation, relative spleen weight, and T-cell count) and peripheral blood glucose levels. Eighteen young (44 days of age) male and female Sprague-Dawley (SD) rats were randomly assigned to one of the 3 housing treatment conditions (1, 3, or 6/cage) and segregated by sex. At the end of 36 days, all animals were injected with 1 ml of a 10% suspension of sheep red blood cells (SRBC). Seven days after immunization, the animals were sacrificed. The results were mixed with regard to the immune parameters investigated. Individually housed animals displayed significantly depressed antibody response when compared to the animals housed 6/cage. There was no main effect of gender on antibody formation. However, male and female animals did differ significantly with regard to peripheral blood glucose level, relative spleen weight, and body weight. The findings from this investigation may suggest that exposure to a presumably stressful event early in life may alter adult host resistance.