Metabolic properties of IgG subclasses in man

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Abstract

Metabolic properties of the four subclasses of human IgG were investigated by performing 47 turnover studies in individuals with normal IgG serum concentrations, as well as in patients with an increased level of one of the subclasses. Studies in 12 subjects with normal IgG serum concentration showed that the average biologic half-life of G1, G2, and G4 was 21 days, while that of G3 was only 7.1 days. Fractional catabolic rates of G1, G2, and G4 were 6.9 to 8% of the intravascular pool per day. G3, however, had a higher fractional catabolic rate, amounting to 16.8% of the intravascular pool per day. Distribution of the subclasses was such that the intravascular compartment contained 51-54% of the total body pools of G1, G2, and G4, but 64% of the total body pool of G3.

Authors

Andreas Morell, William D. Terry, Thomas A. Waldmann