Quantitative estimations of five classes of immunoglobulin in inbred mouse strains

The age-dependent change of the levels of five classes of immunoglobulin in mouse serum were investigated. Between 3 and 12 months after birth, the major IgG subclass of BALB/c was IgG1, while that of C57BL/6 was IgG2b. This difference was the same in the sera from hyperimmunized or germ-free animals.