Effect of differential housing and time on immune reactivity to sheep erythrocytes and Candida

Male C3H/HeJ mice were housed 5 or 1 per cage for varying periods of time. Approximately 10-14 days after the animals were placed under the differential housing conditions, the reactivity of lymphocytes to concanavalin A and to intraperitoneal injection of sheep erythrocytes became greater in animals housed 1 per cage in comparison with those housed five per cage. By 3 weeks the immune reactivity was similar regardless of the number of animals housed per cage. Similarly, resistance to infection with Candida albicans was greater in animals housed one per cage at approximately 10-14 days after the animals had been isolated. By 3 weeks a difference in resistance to C. albicans was not apparent between animals housed 5 or 1 per cage. Thus, housing conditions can transiently alter immunologic reactivity, including susceptibility to an infectious agent in male C3H/HeJ mice. However, female C3H/HeJ mice and male C57BL/6J mice did not show an effect of housing conditions on immune reactions.