Development of lethal autoimmunity after thymic deletion of TR2.

<p>Tamoxifen-treatment of Rag1^−/− mice started 3 d before reconstitution with T-cell–depleted bone marrow from iCD4TR2 or control mice (A–G). (A) Flow cytometric analysis of TR2 expression by CD4⁺ and CD8⁺ T cells at day 34. Representative data of two independent experiments. (B) Body weight was monitored during the whole experiment (mean ± SEM, 5 mice per group, representative data of two independent experiments). (C) Kaplan-Meyer survival graph for all animals of experiments. (D) Representative micrographs of H&E- and anti-CD3-stained tissue sections of indicated organs at day 34. The size bar indicates 100 µm. (E) Flow cytometric analysis of the expression of CD44 and CD62l by CD4⁺ and CD8⁺ T cells. The percentage of T_n and T_em cells in the spleen of experimental and control chimeric mice (mean ± SEM, 6 mice per group, analysed in two independent experiments). (F) Percentage and number of splenic T_reg cells at day 34 (mean ± SEM, 5 mice per group; representative data of two independent experiments). (G) Flow cytometric analysis of FoxP3 and CTLA-4 by indicated splenic CD4⁺ T cells subsets at day 34 (representative data of three independent experiments). Mean florescence intensity of CTLA-4 expression by splenic T_reg cells (right panel, mean ± SEM, 4 mice per group; representative data of three independent experiments). (H) Rag1^−/− mice were reconstituted with T-cell–depleted bone marrow from iCD4TR2 or control mice. Tamoxifen treatment of recipients started 5 wk postreconstitution and body weight was monitored during the whole experiment (mean ± SEM, 5 mice per group; representative data of two independent experiments). (I) The percentage of T_em, cells in the spleen of experimental and control chimeric mice (mean ± SEM, 6 mice per group, analysed in two independent experiments). (J) Tamoxifen-treatment of Rag1^−/− mice started 3 d before reconstitution with T-cell–depleted bone marrow from iCD4TR2 or control mice. At day 15 posttransfer treatment with anti-CD8 antibody or isotype control started. Shown is a Kaplan-Meyer survival graph for all animals in the experiments (representative data of two independent experiments). (K) Representative micrographs of H&E-stained lung sections in the terminal stage of the disease. The size bar indicates 100 µm.