A monoclonal anti-double stranded DNA antibody from an autoimmune MRL/Mp-lpr/lpr mouse: specificity and idiotype in serum immunoglobulins.

Anti-double stranded (ds) DNA antibodies in the sera of lupus-prone MRL/Mp-lpr/lpr (MRL/l) mice were determined by an enzyme-linked immunosorbent assay in parallel with anti-single stranded (ss) DNA, anti-left-handed Z-DNA and anti-poly(ADP-ribose) antibodies. The serum levels of these antibodies in these mice increased with age, and in particular anti-dsDNA antibodies appeared in mice more than 14 weeks old, along with progressive lymphadenopathy. We therefore established a hybridoma producing monoclonal anti-dsDNA antibody (2C10) from an 8-month-old MRL/l mouse. Monoclonal antibody 2C10 did not react with either poly(dT) or poly(I), which are major cross-reactants with previously reported monoclonal MRL mouse autoantibodies. Antibody 2C10 showed preference for phi X-174 replicative form DNA and calf thymus dsDNA over ssDNA. 2C10 idiotype (Id) was present in the sera of MRL/l mice, but only occasionally at high levels even in the aged mice tested. This result suggested that many Ids with anti-dsDNA antibody activity may contribute to lupus pathogenesis in this strain of mouse.