STUDIES ON THE CONTROL OF ANTIBODY-SYNTHESIS .15. EFFECT OF NONSPECIFIC IMMUNODEPRESSION ON ANTIBODY-AFFINITY

The effect on antibody affinity of marked nonspecific immunodepression early in the primary response was studied using three different immunosuppressive agents: 6-mercaptopurine, cyclophosphamide, and heterologous antilymphocyte antiserum. Marked nonspecific immunosuppression, even if limited to an early period in the primary response, resulted in a profound decrease in high-affinity plaque-forming cells (PFC) late in the primary response. Boosting led to the rapid appearance of high-affinity PFC, but the average affinity of the secondary PFC population was low in animals immunosuppressed early in the primary response. It would appear that selection for high-affinity B memory cells took place during the primary response despite the absence of detectable high-affinity PFC in the immunodepressed mice. Finally, the data suggest that in the absence of high-affinity antibody production, there may be an increased production of low-affinity antibodies, presumably as a consequence of a lack of antibody-mediated immunoregulation. © 1979.