Production of IgG-specific auto-anti-allotypes in b4.2-suppressed rabbits

Rabbits were completely suppressed for kappa chain allotype b4.2, and autoantibodies against b4.1 or b4.2 could be raised in 2 out of 3 animals. The animal immunized with b4.1 produced anti-b4 and anti-Ms3, two activities which have never as yet been found together in one antiserum. Both autoantisera lacked the capacity to bind b4.2-IgM, whereas they precipitated 4.2-IgG very well. In one animal, anti-b4 IgM activity appeared after the sixth immunization, at the age of 14 months. Allotype suppression was maintained in both rabbits till the end of their lives whereas all control animals recovered within 6 months. The autoantisera which were specific for b4 IgG could not induce suppression in vivo. However, specific inhibition of b4 IgG secretion was observed in vitro.