NK cells but not B and T cells can be generated in the absence of PU.1.

Seven to 13 weeks after transfer of FL-HSCs, cells were isolated from thymus, BM, and spleen and were stained respectively with mAbs specific for CD8-FITC and CD4-TRI, IgM-PE and B220-TRI, as well as CD3-APC and NK1.1-PE. An electronic gate based on morphologic criteria was set to exclude most nonlymphoid cells. An example of the gating strategy for lymphoid cell analysis in the spleen is shown. Lymphoid organs ofPU.1^−/− chimeras contained virtually no T or B cells, whereas NK cells were present in all chimeras analyzed. Data are from representative of 8 independent experiments.