Chronic high-dose CLs induce spontaneous autoimmune disease in wild-type mice. Eight-week-old female C57Bl/6 mice were injected with the indicated amounts of CLs once a week for a period of 6 months. (A) frozen spleen and kidney sections (5 μm) from mice treated for 6 months as indicated were stained with anti–mouse IgG FITC to examine spleen structure, IgG production (spleen), and immune complex deposition (kidney). Image magnification 20×. (B) Sera were collected from mice after 5 months of chronic administration of the indicated amounts of CLs and examined for IgG reactivity to dsDNA by ELISA as described. (C) Survival curve for mice treated as described over the course of a 6-month exposure to CLs or PBSLs. For all experiments, n = 10 mice/group; **P < .01 as determined by the unpaired Student t test. This experiment was repeated twice with similar results.