STUDIES ON THE TERMINATION OF ACQUIRED TOLERANCE TO SERUM PROTEIN ANTIGENS FOLLOWING INJECTION OF SEROLOGICALLY RELATED ANTIGENS.

The tolerant state of rabbits tolerant to BSA was terminated following the injection of arsanil—sulfanil—BSA and native HSA. Although the injection of soluble arsanil—sulfanil—BSA usually resulted in the loss of tolerance to BSA, it was more effective if it was incorporated into Freund's adjuvant. The incorporation of mycobacteria into the adjuvant resulted in a further increase in the level of circulating anti-BSA. On the other hand, the incorporation of HSA into complete Freund's adjuvant had little enhancing effect on the termination of BSA tolerance following injection of HSA, although there was an enhancement in the production of circulating anti-HSA. Simultaneous injection of soluble BSA with HSA or arsanil—sulfanil—BSA interfered with the termination of BSA tolerance. It was possible to terminate the tolerant state of rabbits tolerant to BGG following injection of HGG but not following injection of aggregated BGG.