Abstract
Bradykinin was added to lymphocyte suspension separated from lymphnodes of the normal and immunized guinea pig. This was incubated at 37°C for 24 h in 5% CO2. Supernatant solution obtained by centrifugation was dialyzed and further filtrated with millipore filter. The supernatant showed a suppressive effect on various immune response and was designated as bradykinininduced suppressor factor (BSF). The effect of BSF on various reactions was studied and the following results were obtained:
1) BSF prepared from the lymphocytes of the immune guinea pig suppressed MIF production using peritoneal exudate cells of the normal guinea pig, lymphocytes of the immune guinea pig and antigen. The suppressive effect of BSF on MIF production was dose dependent.
2) Antigenic lymphocyte proliferation isolated from the lymphnodes of the immune guinea pig was measured with 3H-TdR incorporation and the suppressive effect of BSF was clearly demonstrated.
3) BSF was prepared from all lymphocytes separated from the lymphnodes, spleen and thymus of the immune guinea pig. Of the highest activity was the BSF prepared from the guinea pig 2 weeks after immunization.
4) BSF could be prepared from the lymphocytes of both normal and immunized guinea pigs. However, BSF activity prepared from the immune lymphocytes was more remarkable.
5) BSF production was blocked by the addition of H2-antagonist (burimamide).
