Polyreactive IgM antibodies generated from autoimmune mice and selected for histone-binding activity.

A panel of histone-reactive IgM mAbs was obtained from mice belonging to various spontaneously autoimmune strains. Most of these antibodies were polyreactive, i.e. they showed binding to other cationic antigens (poly-L-lysine, lysozyme, cytochrome c) or to cytoskeletal proteins (actin, myosin, vimentin). The variable regions of these antibodies were encoded by V genes and gene segments belonging to various families. Their H chain third hypervariable regions were unusual in that the D segments were read in all three possible reading frames in contrast to most conventional antibodies and other polyreactive antibodies obtained from normal mice.