Bone marrow clones representing an intermediate stage of development
between hematopoietic stem cells and pro-T-lymphocyte or pro-B- lymphocyte
progenitors
R Palacios and J Samaridis
Basel Institute for Immunology, Switzerland.
We have established in culture several nontransformed bone marrow clones
(called PR) that show phenotypic and genotypic characteristics that
distinguish them from totipotent stem cells and lineage-restricted Pro-T
lymphocytes, Pro-B lymphocytes, and myeloid cell progenitors. In vivo
and/or in vitro the PR clones give rise to T lymphocytes, B lymphocytes,
and some myeloid-lineage cells, but they appear not to be able to generate
cells of the erythroid lineage, nor can they rescue mice from a lethal dose
of irradiation. We conclude that the PR clones are precursor cells
representing an intermediate stage of development between the totipotential
stem cell and lineage-restricted progenitor cells. The results described
here support a model of blood cell formation in which stem cell
differentiation is a progressive process marked by the stepwise loss of
self renewal and functional potential. In addition, they provide evidence
that cytokines and specialized microenvironments can direct the fate of the
developing multipotent progenitor cells.
Volume 81,
Issue 5,
pp. 1222-1238,
03/01/1993
Copyright © 1993 by The American Society of Hematology
