Diabetes-free survival and donor chimerism in NOD mice conditioned with nonmyeloablative (sublethal) radiation. A: Transplantation of 8-week-old NOD mice with B6.H-2g7 bone marrow (8 × 106 cells) or HSCs (4,000 cells) blocks diabetes development after sublethal irradiation with 500 cGy (HSC, ○; bone marrow, •)
or 700 cGy (HSC, □; bone marrow, ▪). Control NOD mice conditioned with 500 cGy (▿) or 700 cGy (▾) and infused with NOD HSCs
developed diabetes (P < 0.001). B: Donor cell chimerism at four different time points posttransplantation for NOD mice conditioned with 500 cGy and transplantation
of B6.H-2g7 HSCs (top panels; n = 14) or bone marrow (bottom panels; n = 8). Multilineage mixed chimerism in peripheral blood was observed in recipients of both graft types in the T-cell, granulocyte/macrophage,
and NK cell lineages. In contrast, host B-cells appear more radiosensitive, resulting in near complete conversion to donor
B-cell type. Chimerism data for recipients conditioned with 700 cGy and transplantation of B6.H-2g7 HSCs are shown in Table 1. Data for the 700 cGy group transplanted with B6.H-2g7 bone marrow are not shown.