Abstract-Effectsof restraint stress on humoral immune responses were investi gated in mice. Mice were restrained for 12 hours per day at nighttime and released at daytime for 2 consecutive days, either before or after sheep red blood cell (SRBC) immunization.The antibody response to SRBC was markedly suppressed in mice that were restrained before antigen injection.In contrast, the response was not significantly affected when the stress was loaded after immunization.Oral admin istration of 10 mg/kg diazepam prevented the stress-induced suppression of anti SRBC antibody response.On the other hand, antibody responses to T cell independent antigens such as trinitrophenylated (TNP)-Ficoll and TNP-lipopolysac charide were not suppressed.These results suggest that the restraint stress causes dysfunction of T cell populations in mice.

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