Activities of four purified growth factors on highly enriched XXXX hematopoietic progenitor cells.

@entity1 @entity2843 @entity2841 @entity1261
The activities of four purified @entity1 growth factors: biosynthetic (recombinant) @entity2841 ( @entity2841 ); recombinant @entity2843 (EPA); natural and recombinant @entity1261 ( @entity1261 ); and natural @entity1261 alpha ( @entity1261 alpha), were compared on the growth of hematopoietic colonies from enriched populations of @entity1 marrow and blood progenitor cells. Conditioned medium from the Mo T cell line (MoCM) was used as a standard positive control. We found that activities of @entity2841 and @entity1261 alpha on the growth of hematopoietic colonies were indistinguishable; @entity1261 alpha is now believed to be identical to @entity2841 . Both factors were able to promote the growth of colonies derived from subpopulations of CFU-GM, BFU-E, and CFU-GEM. Colonies derived from CFU-GM and CFU-GEM in cultures stimulated by @entity2841 and @entity1261 alpha were much smaller than in cultures stimulated by MoCM. In contrast to previous reports in which less highly enriched progenitors were used as target cells, @entity1261 had no detectable activity on the growth of colonies derived from BFU-E or CFU-GEM but promoted the growth of a subpopulation of CFU-GM derived colonies. @entity1261 is now recognized to be identical to @entity1261 . The GM colonies in cultures stimulated by @entity1261 ( @entity1261 ) were much smaller than in cultures stimulated by MoCM. EPA had no detectable activity on either the size or number of colonies derived from CFU-GM, BFU-E, or CFU-GEM. Results from experiments using target cell populations of marrow fractions separated by velocity sedimentation and marrow populations following freezing suggested that @entity2841 ( @entity1261 alpha) and @entity1261 ( @entity1261 ) primarily affect the growth of relatively mature subpopulations of progenitor cells. It is clear from these results that additional factor(s) are present in MoCM that are necessary to stimulate CFU-GM, BFU-E, and CFU-GEM maximally in vitro.
