Exposure to conspecific alarm chemosignals alters immune responses in BALB/c mice

Male BALB/cJ mice were exposed for 24 h to odors from donor mice that were either footshocked or undisturbed. Mice exposed to odors from footshocked donors had suppressed splenic IL-2 production following in vitro concanavalin A (Con A) stimulation compared to home cage or apparatus controls. Stress odor exposure also resulted in reduced natural killer (NK) cell cytotoxicity against YAC-1 tumor target cells compared to controls. Stress odor exposure 24 h after intraperitoneal injection of keyhole limpet hemocyanin (KLH) increased IgM and IgG antibody titers relative to the response of home cage or apparatus control animals. These results demonstrate that exposure to olfactory cues from stressed rodents alters both cellular and humoral immune responses. This paradigm may provide an ethnologically appropriate model of psychosocial stress in rodents.