Murine lupus strains differentially model unique facets of human lupus serology

Systemic lupus erythematosus (SLE) is a polygenic autoimmune disease characterized by the production of anti-nuclear autoantibodies that lead to subsequent end organ damage. Previous array-based studies in patients with SLE have shown that high immunoglobulin (Ig)G anti-nuclear autoantibody reactivity was associated with severe renal lupus, whereas IgM polyreactivity was associated with less severe disease. To ascertain how different murine lupus strains recapitulate these different autoantibody profiles seen in patients, serum from New Zealand black (NZB)/NZ white (W) F ₁, Murphy Roths large (MRL)/lpr, NZ mixed (M)2410 and BXSB strains were compared using a comprehensive array-based screen. The array results were verified using enzyme-linked immunosorbent assays (ELISAs). Serum from MRL/lpr mice exhibited high levels of IgG anti-nuclear antibodies as well as anti-glomerular antibodies and variable levels of antibodies to myosin, Matrigel and thyroglobulin. Elevated anti-nuclear IgG antibodies were associated with severe nephritis in this strain. In contrast, NZM2410 mice exhibited lower IgG autoantibody levels with less severe nephritis but a significantly higher polyreactive IgM autoantibody profile. ELISA analysis confirmed these results. The NZB/NZW F ₁ and BXSB strains exhibited an intermediate serological profile. Hence, just as in patients with SLE, whereas strong IgG reactivity to nuclear antigens is associated with severe renal disease, a polyreactive IgM seroprofile is also less ominous in murine lupus.