Flow cytometry analyses of BM cells after serial transplantation.

Lethally irradiated Ly5.1 primary recipient animals received either wild-type or transgene Ly5.2 donor cells (2-4 × 10⁶unfractionated BM cells). After 6 to 8 weeks, BM was harvested from the recipient animals, stained with fluorochrome-labeled antibodies as shown, and analyzed by flow cytometry to determine their origin (donor or endogenous). Secondary recipients received BM from several of these primary recipient animals. Tertiary transplants were performed in a similar fashion after 6 to 8 weeks of engraftment in secondary recipients. All recipient animals received epo supplementation for a period of 2 weeks after BM transplant. Shown is a representative sample of the BM from wild-type (A) and transgene donor (B) transplanted secondary recipients analyzed by flow cytometry. Note the presence in the recipient animals of both donor (right upper quadrant) and recipient (left upper quadrant) T cells and donor and recipient myeloid/B cells (right lower quadrant and left lower quadrant, respectively) present in the recipient animals.