Immune Degradation in Passively Sensitized Mice

Abstract

Summary Mice were injected with a constant amount of radioactive iodine (I*)-rabbit anti-bovine serum albumin (BSA) and concomitantly with different amounts of BSA such that the zones of antigen excess, equivalence and antibody excess were included. It was shown that both the amount and the rate of immune degradation of I*-rabbit anti-BSA were dependent on the amount of antigen injected. At equivalence the onset of immune degradation was rapid whereas in the zone of antigen excess the onset was delayed. In antibody excess the rate of degradation only slightly exceeded that of the controls. The degradation of I125-labeled antibody and of I131-labeled antigen were followed simultaneously. A constant amount of I125-RγG (rabbit γ-globulin) was injected with different amounts of I131-BSA representing combinations in antigen excess, equivalence and antibody excess. In each case there was an apparent delay in the onset of immune degradation of the antibody, whereas the immune degradation of the antigen began immediately except in antibody excess. Possible explanations for these results were discussed. The data support the idea of constant rearrangement of complexes in vivo such that the instantaneous rate of degradation is a function of the actual ratio of antigen-to-antibody remaining. The data also suggest that more than one type of antibody is involved in accelerated degradation and retention of labeled antigen.