Adoptive transfer of WT Treg prevents autoimmunity in mice with Dnmt1−/− Foxp3+ Tregs. We adoptively transferred 2 × 106 WT Treg intravenously to fl-Dnmt1/Foxp3cre (Dnmt1−/−) mice at 2 days of life and assessed immunopathology at 3 weeks compared with fl-Dnmt1/Foxp3cre without treatment and littermate control (Foxp3cre). (A) CD4+Foxp3+ Treg population is normalized in Dnmt1−/− mice adoptively transferred with WT Treg. (B) CD4 and (C) CD8 Tcon showed a reduced level of activation in fl-Dnmt1/Foxp3cre mice treated with WT Treg. (D) Normalization of key hematologic parameters and (E) reduction of increased immunoglobulin levels in Dnmt1−/− mice after WT Treg administration. (F) Rescue of Dnmt1−/− mice with WT Treg alleviates autoimmune pathology of the lung and liver; hematoxylin and eosin staining, ×200 magnification. (G) Sera from Dnmt1−/− mice without WT Treg treatment (lower row) contained antibodies against nuclei (3 of 3 mice, nucleolar pattern in, eg, liver, 1/40 to 1/80 titers), smooth muscle (3 of 3 mice, eg, colon, 1/10 to 1/40 titers), striated muscle (3 of 3 mice, 1/20 to 1/80 titers), stratified squamous keratinizing epithelium in the skin (2 of 3 mice, ear section, 1/20 to 1/80 titers), and against sperm cells (1 of 3 mice, 1/10 to 1/20 titers). Sera from Dnmt1−/− mice with WT Treg treatment (upper row) had no autoantibodies in corresponding tissues and were indistinguishable from WT controls, with the exception of low smooth muscle antibody titers (1 of 3 mice, 1/10) and striated muscle antibodies (1 of 3 mice, 1/10 titer). All data are shown as mean ± SEM with n = 3 to 4 mice per group. *P < .05, **P < .01, ***P < .001 (analysis of variance with Tukey’s multiple comparison test).
