Evaluation of immunologic assays to determine the effects of differential housing on immune reactivity.

The mechanism is being investigated to determine specifically how an environmental variation such as differential housing can influence the multiple components of the host defense mechanism. Male C3H/HeJ mice were housed either one or five per cage. Cells and sera from these mice were analyzed and compared by several immunologic techniques to determine in which cells or tissues the effect of differential housing was most pronounced. The individually housed mice (a) had a greater capacity to phagocytose dead cells of Candida albicans. (b) had spleens that produced more macrophage colony stimulating factor (M-CSF). (c) were more responsive to M-CSF, (d) had peritoneal macrophages that released greater quantities of interleukin-1 in vitro into the surrounding medium and that had a greater capacity to migrate toward a chemotactic stimulus, and (e) had higher titers of IgM hemagglutination antibody to sheep erythrocytes. Differential housing of mice may therefore be a highly important modulator and indicator of the nature and extent of an animal's immunologic response to an environmental stimulus.