Immune Degradation in Passively Sensitized Mice^1,2: I. Degradation of Antigen as a Function of the Amount of Antigen and Antibody Used

Whole-body counting was used to study the degradation of I¹³¹-labeled antigen in passively sensitized mice.

In passively sensitized mice, antigen is degraded at an accelerated rate. ADAR (antigen degraded at the accelerated rate) is the difference at any time (t) between the residual antigen in the passively sensitized mouse and in normal mice expressed as a per cent of residual antigen in the normal.

97–99% of the antigen was degraded at an accelerated rate in mice injected with antigen-antibody ratios that correspond to equivalence or antibody excess in vitro.

Antigen is degraded at an accelerated rate in mice injected with ratios of antigen to antibody that are in antigen excess in vitro, and are associated with little or no precipitation.

The ADAR is inversely related to the amount of antigen used if the amount of antibody is held constant and if the antigen-antibody ratios are in antigen excess in vitro.

In mice injected with antigen-antibody ratios which are in antigen excess in vitro, the amount of antigen degraded at the accelerated rate is estimated to be greater than the amount precipitated at equivalence.

The accelerated degradation of the antigen in passively sensitized mice is completed 6–10 hr after the antigen is injected, and the half time of the accelerated degradation is independent of the antigen-antibody ratios used.

The ADAR (determined at 24 hr) is a function of the amount of antibody used when the amount of antigen injected is held constant.