Figure 1.

Representative photomicrographs of the descending colon of RAG-2^−/− mice after transfer of subpopulations of CD4⁺ T cells from WT or IL-10^−/− mice. (A) Severe colitis in a mouse injected with CD45RB^high CD4⁺ T cells from WT mice. (B) Normal appearance of the colon in a mouse restored with WT CD45RB^high and WT CD45RB^low CD4⁺ T cells, indicating that the WT CD45RB^low population is able to inhibit disease induced by WT CD45RB^high CD4⁺ T cells. (C) Severe colitis in a mouse cotransferred with WT CD45RB^high CD4⁺ T cells and IL-10^−/− CD45RB^low CD4⁺ cells, indicating that the IL-10^−/− CD45RB^low subpopulation is unable to protect from the disease. (D) Severe colitis in a mouse receiving only IL-10^−/− CD45RB^low cells, indicating that this population is able to induce disease. Hematoxylin and eosin; original magnifications: ×50.