[Study of the subclasses of immunoglobulin G. II. Qualitative and quantitative characteristics of IgG subclasses...

Bispecific antisera, or "antisera-systems", containing class- and subclass-specific antibodies to IgG were obtained from rabbits, goats and guinea pigs after brief courses of immunization with purified G1, G2, G3 and G4 paraproteins. After the elimination of antibodies to light chains by adsorption these antisera were tested in immunoelectrophoresis and radial immunodiffusion in gel with sera containing G paraproteins of different subclasses. In immunoelectrophoresis double lines and in radial immunodiffusion with G paraproteins of heterologous subclasses double rings were obtained: the external lines (or the external rings) were formed as a result of interaction between G paraproteins and antibodies to class-specific IgG determinants, the inner lines (or the inner rings) were formed as a result of interaction between the corresponding subclass of normal IgG and subclass-specific antibodies. The identification of different G paraprotein subclasses gave similar results when carried out with "antisera-systems" and with monospecific antisera to the corresponding IgG subclasses. "Antisera-systems" proved to be suitable for use in the identification of G paraprotein subclasses, as well as in the quantitation of different subclasses in normal IgG.