Analysis of engraftment 8 weeks after implantation showed low-level detection (<0.1%) of BFP+ cells with positivity for CD11b+ myeloid and B220+ lymphoid compartments in BM of 1 recipient (Figure 4D, Figure 4—figure supplement 2F-G); a fourth recipient had to be sacrificed early due to infection. This evidence concerns the gene PTPRC and infection.