Immunological consequences of the reversal of social status in C57BL/6J mice

The present study has shown that the immune response can be influenced by the reversal of animal's social status. For this purpose testing of agonistic interactions under the sensory contact conditions was performed for pairs of either aggressive or submissive C57BL/6J male mice with preliminary experience of 10 or 20 daily confrontations. Tests continued for 10 or 20 days, respectively. The reversal of aggressive behavior into submissive one in C57BL/6J mice resulted in immunosuppression only following 20 daily confrontations compared to the controls as well as to aggressive males which did not change their behavior and showed the increased immune response. Despite the fact that previous experience of defeat was associated with a reduced immune reaction, the occurrence of aggressive behavior in formerly submissive mice during 10 or 20 tests of daily confrontations produced immunostimulation. It is suggested that changes in the neurochemical pattern of the brain can be considered as an underlying basis for the linkage between the immune response and specific behavioral profile.