Inactivation of GFP expression occurs primarily as stem cells differentiate into lymphoid cell populations.

Bone marrow cells were stained with antibodies directed against markers that define specific blood cell lineages, including B cells (B220), monocytes and neutrophils (Mac-1 and Gr-1), primitive erythrocytes (Ter-119), natural killer cells (NK-1.1), and T cells (CD3). Contour plots showing mature lineage marker expression are gated for all donor-derived (Ly-5.2) cells.