SUPPRESSION OF ANTIBODY RESPONSE AND PROLONGATION OF SKIN GRAFT SURVIVAL BY MULTIPLE BLOOD TRANSFUSIONS IN THE RAT

Abstract
The effect of blood transfusions (BT) on antibody response and skin graft survival was studied in the strongly MHC-incompatible BN and LEW combination. One-to-three BT induced high titer antibodies. Additional BT, however, led to a decrease of antibody titers. After 15 BT the recipients either had no detectable antibodies, or they had very low antibody titers. This suppression of response was shown to be distinct from a simple loss of antibody activity caused by lack of further antigenic challenge. In multiple transfused rats, humoral nonreactivity persisted in spite of rechallenge with antigen; in animals that lost their antibodies as a result of lack of further stimulation, an additional BT boosted strong antibody production. In LEW recipients of multiple BN transfusions, not only the specific anti-BN response but also reactivity to third-party BUF blood was suppressed. However, whereas the donorspecific response (anti-BN) was largely inhibited after a ten-week interval, the response to third-party BUF blood recovered. The state of humoral nonreactivity could be transferred by spleen cells to nontransfused syngeneic animals. In LEW rats that received three injections of 5 x 107 “suppressor” spleen cells, the antibody response to BN blood was strongly impaired as compared with animals that received normal spleen cells. BN or (BNxLEW)F1 skin grafts survived significantly better in multiple transfused LEW rats than in nontransfused controls. This was even more pronounced when ALS was given additionally. Third-party grafts (BUF) survived only slightly better than controls. It is concluded that multiple BT (1) result in humoral anti-donor nonreactivity secondary to an initial antibody response, (2) induce strong specific and weak nonspecific suppressor cell activity, and (3) increase skin graft survival.