THE IMMUNOGLOBULINS OF MICE : II. TWO SUBCLASSES OF MOUSE 7S γ(2)-GLOBULINS: γ(2a(-))ANDγ(2b)-GLOBULINS

Two subclasses of mouse 7S γ(2)-globulins are identified, and are designated γ(2a)- and γ(2b)-globulins. They are distinguished from 7S γ(1)-globulins, γ(1A) (β(2A))-globulins, and γ(1M)-globulins of mouse serum. Antibody activity was detected among the γ(2a)-globulins and γ(2b)-globulins of hyperimmune mouse serum. γ(2a)- and γ(2b)-myeloma proteins were identified. The genetically determined isoantigen, Iga-1, was present on γ(2a)-myeloma proteins, but not on γ(2b)-myeloma proteins. These findings indicate a complexity among the 7S γ(2)-globulins which must be taken into account in structural, functional, and genetic studies of immunoglobulins.