SHORT AND LONG RESTRAINT DIFFERENTIALLY AFFECT HUMORAL AND CELLULAR IMMUNE FUNCTIONS

The aim of this work was to examine the effect of different periods of restraint on the humoral and cellular immune functions in adult male rats. Short restraint stress (2 h over 2 consecutive days) enhanced th e primary serum antibody response to sheep red blood cells. The enhanc ement of this humoral response was dependent on the restraint period, since long restraint stress (6 h over 4 days) failed to modify this re sponse. Short and long restraint decreased both the number of lymphocy tes and the T-lymphocyte response to Con A stimulation in the peripher al blood. Neither 2 h over 2 days nor 6 h over 4 days modified the spl enic lymphoproliferative response to Con A stimulation, but restraint stress progressively decreased the number of mononuclear splenic cells . Both periods of restraint significantly increased plasma concentrati on of corticosterone, however plasma prolactin levels were significant ly lower after 4 days of restraint but not after short restraint (2 h over 2 days). These results indicate that although some immune functio ns can be increased after acute or short stress, long stress has an im munosuppressive effect, above all on the cellular immunity which is mo re susceptible to this effect than the humoral response.