International Journal of Cell Cloning, Vol 10, 241-248, Copyright © 1992 by AlphaMed Press
Differentiation profiles of normal blast cell colonies derived from mononucleated cells, T cell depleted nonadherent cells and CD33- negative, CD34-positive normal human bone marrow cells
Y Hirota, N Jamal and HA Messner
Ontario Cancer Institute, University of Toronto, Canada.
Blast cell colonies can be grown reproducibly in methylcellulose from
normal human mononuclear bone marrow cells (MNC) in the presence of 30%
human plasma, 1 U human recombinant erythropoietin and 10% of medium
conditioned by phytohemagglutinin stimulated leukocytes as a source of
growth factors. The colonies can be recognized by inverted microscopy by
their display of highly refractile cytoplasmic structures that resemble
small vacuoles. A proportion of cells within these colonies remains
CD34-positive (CD34+). The blast-like morphology of these cells was
sustained for at least 14 to 21 days. The frequency of blast cell colony
forming units (CFU-BL) can be increased by a series of separation
procedures to produce E-rosette depleted, nonadherent cells (E-NAC), CD34+
cells and CD33-CD34+ cells. The mean number of CFU-BL per 10(5) cells was
1.9 +/- 1.6 in MNC, 5.7 +/- 2.7 in E-NAC, 108 +/- 51 in CD34+ cells and 112
+/- 109 in CD33-CD34+ cells. The enrichment procedures were not specific
for CFU-BL but also resulted in a similar increase of multilineage and
single lineage progenitors. The relative proportions of CFU-BL and other
progenitors remained unchanged among these subpopulations. The size of
individual blast cell colonies on day 16 varied from 20 to 1,600 cells.
After 14 to 21 days, cells within blast cell colonies acquired mature
morphological features. The majority of blast cell colonies developed into
multilineage colonies (62%); some (38%) were restricted to a single
hemopoietic lineage. Larger blast cell colonies had a higher probability of
developing into multilineage colonies than smaller blast cell colonies.
