The metabolism of different immunoglobulin classes in irradiated mice

Abstract

The catabolism of the different classes of immunoglobulins (Ig) of normal and irradiated mice was studied. A lethal dose of X-rays brought about no significant alterations in the catabolic rates of IgM and IgA, which kept to a time of about 12 hours. Contrariwise, the IgG (IgG₁, IgG_2a and IgG_2b) displayed a distinctly accelerated catabolism in the irradiated mice, the half-life of these Ig's being reduced by approximately one-half. We propose an interpretation of this phenomenon, based, on one hand, on the great radiosensitivity of the intestinal epithelium and, on the other hand, on the mode of catabolism of IgM and IgA which appears to be different from that of IgG.