Colony-forming cells in XXXX --I. Proliferative responses to growth factors.

@entity1 @entity1860 @entity1307 @entity1014
Peripheral blood cells from 2 @entity1 with @entity1860 were separated by density centrifugation. Mononuclear cells of low density (d less than 1.062g cm-3) with blast-cell morphology were cryopreserved before culture in vitro. Upon culture in conventional colony assays, up to 20% of the cells formed hemopoietic colonies. Although the spectrum of colony types resembled that of normal bone-marrow cells, there were large differences between the @entity1 with respect to the number, type and size of colonies that were observed. Colony formation required the addition of hemopoietic growth factors, such as colony-stimulating activity and @entity1307 to the culture medium. The cells were used to assay hemopoietic regulatory molecules. Both @entity1307 and colony-stimulating activity induced a strong proliferative response as measured by @entity1014 incorporation. Maximal stimulation was observed when @entity1307 and the supernatant of mixed lymphocyte cultures were added simultaneously. The difference between the cells from the 2 @entity1 in clonal assays was reflected by the different response to individual hemopoietic regulators. The time course of maximal stimulation followed distinct patterns dependent on the source of stimulator. The stimulation was linearly dependent on the input cell number. Taken together, cryopreserved blast cells from @entity1 with @entity1860 appear to be very useful for the characterization of factors regulating hemopoiesis, as well as for studies of hemopoiesis in general.
