Comparison of the hematopoietic progeny in the secondary recipients 4 weeks after IV transfer of cells from thymus and from blood of the primary recipients.

T-cell– and mature B-cell–depleted BM cells from C57BL/6 (Ly-5.2) mice were injected intravenously into lethally irradiated primary Ly-5.1 recipient mice. Four days after primary transfer, thymus cells and blood cells were harvested from the primary Ly-5.1 recipients and injected intravenously, respectively, into lethally irradiated secondary Ly-5.1 recipients as described in Figure 5. Four weeks after reconstitution, donor-derived cells in the spleen plus lymph nodes and in the BM of the secondary recipients were analyzed by flow cytometry using the procedures described in “Materials and methods.” Stainings for lineage markers on the Ly-5.2⁺ donor-derived cells in the secondary recipients transferred with the thymus cells of primary recipients are shown in panel A. Stainings for lineage markers on the Ly-5.2⁺ donor-derived cells in the secondary recipients transferred with the blood of primary recipients are shown in panel B.