IL23R and colitis: Despite the increased frequencies of Treg cells observed in the colon of mice transferred with Il23r−/− T cells, the incidence and severity of colitis in mice receiving a mixture of CD45.2− WT plus CD45.2+ WT or CD45.2− WT plus CD45.2+Il23r−/− T cells was almost identical, indicating that Il23r−/− T cells do not possess dominant suppressive activity (Figure 6E).