Fig. 6. Integrin-α4β7 dependent localization in the pancreas is required for protection by aTreg cells.

(A) NOD.Scid mice were injected with Thy1.1⁺ BDC2.5 aTreg cells. Ten days after cell transfer, pancreata from recipients were analyzed for islet localization of transferred aTreg cells by staining with Thy1.1-(red) and insulin-(green) specific antibodies. Representative images were shown at a magnification of 40X. (B) BDC2.5 Thy1.1⁺ aTreg cells were tested at the time of harvest for expression of the integrin chains, α4, αE, and β7. (C) NOD.Scid mice were injected with Thy1.1⁺ BDC2.5 aTreg cells and treated at the time of cell transfer with either anti-integrin-α4 antibody or control IgG in a dose of 200μg/recipient (n = 4/group). The mice were treated again on day 3, and the tissues were harvested and analyzed on day 7 for the recovery of CD4⁺Thy1.1⁺ donor cells (mean ± SEM). (D) Polyclonal aTreg cells were differentiated from CD4⁺CD25⁻ cells from NOD and NOD.β7^−/− mice and injected into NOD.Scid recipients. Two months later, the indicated tissues were harvested, pooled, and analyzed for the presence of CD4⁺Thy1.1⁺ donor cells. (E) Young prediabetic NOD mice were injected with splenic cells from diabetic donors. Two weeks later, these mice were given polyclonal aTreg cells differentiated from WT NOD (n = 12), NOD.integrin-β7^−/− (n = 6), or were not treated with aTreg cells (control, n = 9). Blood glucose levels and diabetes incidence were monitored weekly.