Inheritance of Responsiveness of Tolerant Animals to a Cross-Reacting Antigen

Random-bred rabbits were rendered tolerant to human serum albumin (HA) by neonatal injections. Starting at 44 days of age, the rabbits were injected i.v. with para-azobenzenesulfonic acid human albumin HA-D₃₁). Animals which made an antibody response (TCR-responders) were matea with each other, as were animals, which failed to make an antibody response (TCR-nonresponders). TCR-nonresponsiveness was found to breed true after 3 generations of selective matings. TCR-responsiveness did not appear to be correlated with tolerance duration or with any of the allotypic specificities (A1,2,3,) controlled at the Aa locus. There were no C6-deficient animals among TCR-responders nor among TCR-nonresponders. There was a slightly lower responsiveness to HA-D₃₁ of TCR-nonresponders which were not injected at birth than of unselected animals.