Catabolic Half-Lives of Immunoglobulin and Albumin as a Function of Age in Mice

Abstract

Humoral immune activities generally decline in both mouse and man as the individual ages. It is not known what role the catabolism of immunoglobulin plays in the decline. To have a better insight into this problem, the catabolic half-lives of radioiodinated immunoglobulin and albumin were assessed in mice 3 to 35 mo. of age. In itial studies on total serum protein, albumin, and immunoglobulin g concentration revealed that they tend to vary with age. The half-life of immunoglobulin g decreased sharply until about 6 mo. of age, followed by a more gradual decrease throughout the remainder of life. On the other hand, the half-life of albumin remained relatively constant until very late in life, when a marked increase was observed.