Abstract: The effect of frequency of emotional stressor presenting and the order in which emotional stress and antigen immunization occurred on the humoral immunomodulati on of emotional stress was studied in adult male Wistar rats. Emotional stress w as induced by randomly giving empty water bottles to rats trained to drink water at two set times each day,the specific antigen Ovalbumin (OVA) was used to immu nize the rats. Results showed that before the antigen immunization,three times e motional stress,30 minutes each time,did not influence the level of anti OV A IgG antibody and spleen index (the primary humoral immunity);however,after ant igen immunnization,the same emotional stress decreased the level of antibody and spleen index;and ,14 times emotional stress after antigen immunization,10 minut es each time,suppressed significantly the primary humoral immune function. T aken together,these findings demonstrated that emotional stress can modulate the humoral immune response,but the effect is dependent upon the severity of emotion al stress and the order in which emotional stress and antigen immunization occur red,14 times emotional stress after antigen immunization suppressed the primary humoral immunity.

Key words: emotional stress, humoral immunomodulation, OVA, antibody, sp leen index, the primary humoral immunity