CHRONIC RESTRAINT ATTENUATES THE IMMUNOSUPPRESSIVE RESPONSE INDUCED BY NOVEL AVERSIVE STIMULI

The exposure to a novel aversive event, such as foot shock, induced a decrease in the percentage of T lymphocytes and a clear reduction in t he delayed-type hypersensitivity reaction (DTH). This immunosuppressiv e response to an acute stressor was absent in rats that were previousl y exposed to a chronic immobilization stress regime (2 h daily during 7 consecutive days), but was still present in animals with prior expos ure to only one or three restraint sessions. No stress effect was obse rved in other immunologic parameters, such as the percentage of B lymp hocytes or the hemagglutinin titer, in any of the experimental treatme nts. The possible involvement of central adaptive mechanisms in the at tenuation of the immunosuppressive response induced by an acute stress is discussed.