Partial expression of the viable motheaten (mev) mutation in the heterozygous state: abnormal levels of serum immunoglobulins and natural anti-ssDNA antibodies.

The 'viable motheaten' (mev) mutation in the C57BL/6 (B6) mouse causes a rapidly progressive and fatal autoimmune syndrome in mev-homozygous B6 mice, combined with generalized immunodeficiency, whereas the mev-heterozygous B6 mice look phenotypically normal. However, serological analyses of the levels of some spontaneously occurring, natural antibodies and of the levels and distribution of the different classes of immunoglobulins revealed mild but evident dysregulation of the natural humoral immunity of +/mev individuals.