Lengthened Induction Period or Immunologic Unresponsiveness Depending on Antigen Dose in Adult, X-Irradiated Rabbits

Adult rabbits were injected with either 10 mg or 100 mg of bovine albumin 24 hours after 400r x-irradiation. The dose of irradiation was shown to suppress completely the antibody response to the smaller amount of antigen but not to the larger amount. In the latter case the induction period was lengthened and a delayed antibody response was determined to have occurred sometime between the 14th and 24th day after injection. Whether antibody formation was to be suppressed or delayed could be correlated with the disappearance of radioiodinated antigen from the blood and the amount of antigen remaining. It was further shown that the 10 mg dose of antigen but not the 100 mg dose established a state of immunologic unresponsiveness to a subsequent challenge with antigen.