Donor-derived multilineage hematopoiesis. The PB, BM, and spleen of chimeric recipients was evaluated for the presence of Ly5.1⁺ donor cells 4 weeks after in utero transplantation. (A) The percentage of total cells that express either a lineage-specific marker and/or Ly5.1 in the PB of a representative recipient is indicated. (B) The mean and SEM of the frequency of lineage-specific, donor-derived cells in the PB, BM, and spleen of chimeric recipients (n = 6) is shown. (□) CD3; (▨) B220; (▪) Mac-1/Gr-1.