Human IgG subclass study. II. The levels of the individual IgG subclasses in paired sera from mothers and newborn infants as well as in the blood sera of inhabitants of an isolated northern village]

The levels of the first 3 subclasses of IgG, as determined by the radial immunodiffusion test, proved to be similar in the blood sera obtained from mothers and newborns in Moscow. The concentration of IgG4 was 0.64 +/- 0.02 g/l iently indicative of a limited passage of IgG4 molecules through the placenta. The inhabitants of an isolated northern village were found to have the inheritable combined deficit of IfG2 and IgG3 synthesis in their blood sera, which was probably due to the prolonged processes of inbreeding and the progenitor effect.