Bone marrow reconstitution in non-myeloablated w/wv mice

We have documented the kinetics of bone marrow engraftment in non-myeloablateii W/W mice transplanted with increasing numbers of light density wheat germ aglutmin(WGA) -15 1.1 cells purified from normal murine marrow. The cells were further separated on the basis of rhodamine 123 staining into Bright and Dull. Bright or Dull cells ( 10;-104 /mouse) were injected into otherwise untreated W/W mice and the percent of engraftment evaluated by harvesting every month for the life of the animals, 100-200 uL of blood. Red cells and mononuclearcells (WBC) were separated by centnfugation and the percent of circulating host and donor red cells and WBC established on the basis of the type of hemoglobin and of the c-Kit genotype which they expressed, respectively. Mice injected with Rho-bright cells were either not engrafted or transiently engrafted (i.e. =50% of donor red cells for a limited period of time and 40-50% of donor WBC for life). Mice injected with Rho-dull cells were either permanently engrafted at high (i.e. >99% donor red cells and >50% donor WBC) or at low (<1% donor red cells and 10-40% of WBC) levels. Rho-bright and -dull cells were repurified from mice transplanted with Rho-dull cells. Interestingly, mice with high engraftment levels had 20-30% of the Dull and 80-90° n of the Bright cells with the donor genotype while mice with low engraftment levels had < 1% of the Dull and -420-30% of the Bright cells with a donor genotype. The different frequency of donor Dull cells in permanently reconstituted W/WA mice with high or low levels of engraftment might discriminate between two different reconstitution profiles and argues against the calculation of purity of a slum cell population on ihe basis of the results of all the reconstituted animals.