FOXP3 and colitis: Intracellular staining of FoxP3 in spleen-derived CD4+ T-cells of mice with T-cell transfer-induced colitis (Figure 2D, E) showed enhanced numbers and percentages of FoxP3pos cells, i.e. iTregs, in mice that had received β2i/MECL-1&β5i/LMP7-deficient CD4+ T-cells.