Transfer of diabetes requires host myeloid cells to express the IFNγR. A, Transfer of 4×106 activated BDC T cells or BDC.scid T cells (106) into NOD.Rag.IFNγR+/+ or NOD.Rag.IFNγR−/− recipients and followed for diabetes incidence. While activated BDC T cells transferred diabetes into NOD.Rag.IFNγR+/+, the transfer of either activated BDC.NOD T cells or BDC.scid cells into NOD.Rag.IFNγR−/− did not increase diabetes incidence. Experimental mice were followed for 60 days post T cell transfer. B, Bone marrow chimeric mice in which the bone marrow derived cells or the β-cells expressed or did not express IFNγR were transferred with activated BDC, T cells (4×106) and followed for diabetes incidence for 30 days. Only recipient mice that contained bone marrow derived cells that lacked IFNγR and β-cells-expressing IFNγR were free of diabetes. C, Islets from previous mice that were free of diabetes (day 30, last day of observation) were examined for insulitis by H&E sections. Data obtained from 24 experimental mice.