IgA polymorphism in mice: NZB and BALB/c mice produce two forms of IgA.

There are two different forms of mouse IgA immunoglobulins, one in which light chains are disulfide-linked to each other (IgAL-L) and the second where light chains are linked to heavy chains (IgAH-L). IgA myeloma proteins from BALB/c mice are IgAL-L and those from NZB are IgAH-L. To determine whether these two forms of IgA represent allotypic or isotypic variants, we purified serum IgA and prepared IgA-secreting somatic cell hybrids from mitogen-stimulated BALB/c and NZB mice and determined the pattern of light chain linkage. It was found that each strain produces both forms of IgA and that both forms share the allotypic determinants characteristic of the mouse strain.