Normal T-and B-lineage cells of original donor BM origin were produced by secondary transfer of cells from the primary recipient thymus.

Cells from the thymus of the primary recipients were harvested 5 days after the original BM transfer, then injected intravenously into secondary recipients. Cells from the spleen and lymph nodes of secondary recipients 4 weeks after secondary transfer were then analyzed, as in Figure 5. The original BM-derived Ly-5.2⁺Thy-1.2⁺ and Ly-5.2⁺B220⁺ cells were further examined for the expression of CD3 and CD19, respectively. All original BM-derived Thy-1.2⁺ cells were also CD3⁺, and all the original BM-derived B220⁺ cells were also CD19⁺. Dots and dashes represent background staining.