Fig. 1.
T cell proliferation following Treg depletion is predominantly directed to self antigens. (A) Donor T cell proliferation at day 7 postinjection in lymphoid organs of SPF (n = 3), GF (n = 8), or AF (n = 7) Rag1−/− hosts adoptively transferred with CD44lo CD62Lhi naive CD4 T cells from CD45.1 Foxp3-GFP mice. Also shown are the percentage of fast-dividing (CTV−) T cells in SPF (n = 3) and GF (n = 2) Rag1−/− hosts injected with CD45.1 naive CD4 T cells (1 × 106) ± CD90.1 nTregs (2 × 105). Representative CTV dilution profile on CD45.1 donor T cells in peripheral LN (PLN) (Left), and graph for fast-dividing cells among CD45.1 total donor T cells (Right). (B) Total donor T cell numbers in PLN, mesenteric LN (MLN), or spleen (SPL) of SPF (n = 3), GF (n = 3), or AF (n = 4) Rag1−/− hosts injected with naive CD4 T cells at day 7 postinjection. (C–E) Comparison of induction of lymphoproliferative syndrome at day 10 following PBS or DT treatment of age-matched SPF, GF, or AF Foxp3-DTR mice (n = 2 for PBS-treated mice and n = 4 for DT-injected groups). (C) Representative FACS plots for IFNγ and IL-13 production by SPL Foxp3−CD4+ T cells (Left) after 4 h of ex vivo stimulation in the presence of PMA/ionomycin and protein transport inhibitors, and total numbers of IFNγ+ or IL-13+ CD4+ T cells (Right). (D) H&E staining of sections of liver from Foxp3-DTR mice treated with PBS or DT, raised under SPF, GF, or AF conditions. Scale bars, 100 um. The arrows indicate lymphocyte infiltrations. (E) Total numbers of IL-17A–producing CD4 T cells from MLN (Left) or colonic lamina propria (Right) in mice from each group. P values were determined by Student’s t test or one-way ANOVA with Newman–Keuls multiple-comparison test. Error bars show mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001. Note that details of materials and methods for these and other experiments are provided in SI Appendix, Materials and Methods.