Ability of donor BM CD4⁺ and CD8⁺ T cells to facilitate engraftment.

Graded numbers of sorted C57BL/6 BM CD4⁺ and CD8⁺ T cells were added to constant numbers (750 × 10³) of C57BL/6 TCD BM cells and injected into lethally irradiated BALB/c recipients. Survival over a 100-day observation period is shown for groups of 10 to 20 mice. Data are combined from at least 2 replicate experiments. (A) Graded numbers of BM CD8⁺ T cells. (B) C57BL/6 BM CD4⁺ T cells or BM CD8⁺ T cells from C57BL/6xBALB/c F1 mice. (C) Chimerism of the BALB/c recipients given C57BL/6 TCD-BM cells alone or C57BL/6 TCD-BM and C57BL/6 BM CD8⁺ T cells 100 day after BM transplantation. The spleen cells were stained for anti–H-2K^b versus TCRαβ, B220, or MAC-1 and Gr-1 markers. The donor-type cells are shown in the upper box and host-type cells in the lower box in each panel.