Figure 8.

c-rel^−/− T reg cells inhibit T cell proliferation in culture and suppress CD4 T cell-dependent colitis. Varying numbers of wt and c-rel^−/− T reg cells (suppressors) from various sources (see A–C) incubated in culture with a fixed number of wt splenic CD4⁺CD25⁻ T cells (effectors), expressed as a ratio, were activated with anti-CD3 antibodies and irradiated T cell–depleted APC for 72 h. Proliferation was monitored by ³H-thymidine incorporation. The data shown in A–C is the SEM for four independent experiments using each different source of T reg cells. Every data point was performed in triplicate for each experiment. (A) Splenic T reg cells from wt and c-rel^−/− mice. (B) Foxp3⁺ cells generated by transducing wt and c-rel^−/− CD4⁺CD25⁻ splenic T cells with GFP-Foxp3 retroviruses. (C) Foxp3⁺ cells generated from TGF-β + IL-2–treated wt and c-rel^−/− CD4⁺CD25⁻ splenic T cells. rag-1^−/− mice injected with CD4⁺CD45RB^hi T cells (4 × 10⁵) in the absence or presence of wt or c-rel^−/− CD4⁺CD25⁺ T cells (10⁵, >87% Foxp3⁺) were monitored regularly for up to 10 wk. During this period, mice displaying signs of illness or weight loss were sacrificed. After 10 wk, the remaining mice were weighed and sacrificed. The colons were removed from all mice and processed for histology. (D) Representative hematoxylin and eosin–stained colon sections from rag-1^−/− mice receiving CD4⁺CD45RB^hi T cells alone or with wt or c-rel^−/− CD4⁺CD25⁺ T cells (n = 12 mice for each cohort). Bars, 875 µM. (E) Histology scores for rag-1^−/− mice receiving CD4⁺CD45RB^hi T cells alone or with wt or c-rel^−/− CD4⁺CD25⁺ T cells based on a modification of Berg et al. (1996). *, P < 0.02; **, P < 0.05.