International Journal of Cell Cloning, Vol 3, 44-56, Copyright © 1985 by AlphaMed Press
Heterogeneity within the hematopoietic stem cell compartment: evidence for a marrow-seeding stem cell distinct from CFU-s
JS Duke-Cohan, AJ Davies and VJ Wallis
Using a chromosome marker within a syngeneic system, we investigated the
seeding characteristics of murine hematopoietic stem cells after
transplantation to irradiated hosts. The chromosome-marked test cells were
allowed to compete with normal marrow cells in repopulating the spleen and
marrow of irradiated mice. Although the seeding behavior of normal marrow
could be predicted from the number of colony-forming units-spleen (CFU-s)
transplanted, the marrow seeding of melphalan- treated marrow was 7-fold
greater than expected. Repopulation of marrow by spleen cells was less
effective than expected from the CFU-s content, while the reverse was true
after repopulation by fetal liver cells. These differences were emphasized
after treatment of cell donors with melphalan. The results were due
primarily to differences in the lodging properties of the transplanted
cells, those seeding in the marrow were less sensitive to melphalan than
CFU-s. In some instances marrow-repopulating ability could be separated
from peak CFU-s activity on a density gradient, suggesting a
marrow-repopulating cell exists that is distinct from CFU-s.
