Adoptive transfer of BM cells and spleen cells from Ptpn11^D61Y mice with MPD. (A) BM cells (2 × 10⁶) or (B) spleen cells (5 × 10⁶) from Ptpn11^D61Y (CD45.2) mice were transferred together with 10⁵ CD45.1 WT BM cells into lethally irradiated CD45.1 recipients. The percentage of peripheral blood cells expressing CD45.2 was quantified by flow cytometry at the indicated times. (C) Representative spleen cells from a recipient 24 weeks after transplantation, showing the presence of donor-derived B220⁺, CD3⁺/CD4⁺/CD8⁺, and Gr1⁺ cells.