Flow cytometric and functional characterization of AC133⁺ cells from human umbilical cord blood

Abstract

Summary. AC1331 cells may represent an alternative source of transplantable haemopoietic progenitor cells to CD34 1 cells. Here, we have addressed the characterization of umbilical cord blood (UCB) AC1331 cells and compared their immunophenotypic and functional features with those of UCB CD34 1 cells. UCB AC133 1 and CD34 1 cell fractions were purified by magnetic cell sorting, analysed by flow cytometry, tested for their content in blast cell colonyforming units (CFU-Bl), erythroid and granulocyte±macro-phage colony-forming units before and after expansion in the presence of various haemopoietic growth factor combinations. Median AC133 1 cell yield was 62´3%, and median AC133 1 population purity was 97´9%. AC133 1 cells were found to contain significantly more CFU-Bl than CD34 1 cells; furthermore, the replating efficiency, i.e. the number of CFU-Bl capable of generating secondary colonies, was higher in the former than in the latter cells. Both AC133 1 and CD34 1 cells displayed an increased ability to give rise to committed progenitors after 7-day expansion in liquid cultures. These data suggest that the AC133 1 cell subset is a heterogeneous pool of immature and more differentiated cells that can be maintained and expanded in well-defined culture conditions. In comparison with CD34 1 cells, UCB AC1331 cells appear to contain a higher number of early haemopoietic progenitors.

Ex-Vivo Expanded Umbilical Cord Blood Stem Cells Retain Capacity for Myocardial Regeneration

“…31 Although all cultures were performed with a starting population of CD133 + /CD34 + cells independent of the culture conditions, a balance between 3 different proportions of SC subpopulations, CD133 + /CD34 + , CD133 + / CD34 − and CD133 − /CD34 + , was established after expansion. The CD133 − /CD34 + fraction has been described by other groups as part of the CD34 + SC fraction (~23% of the total number of CD34 + cells in cord blood) with reduced clonogenic potential.…”

Characterization of a Lineage‐Negative Stem‐Progenitor Cell Population Optimized for Ex Vivo Expansion and Enriched for LTC‐IC

“…For reprints contact: Reprints@AlphaMedPress.com 101 hosts [3,5]. CD133 was reported as an alternative marker for positive selection methods targeting more primitive HSPC enriched with CD34 bright cells [6,7]. However, we have recently reported that although CD133 + cells had interesting ex vivo expansion potential, they still encompassed cells at various stages of differentiation [8].…”

IL‐3‐Dependent Early Erythropoiesis Is Stimulated by Autocrine Transforming Growth Factor Beta

“…CD133 + stem cells with erythroid potential represent mostly an immature subpopulation of CD34 + stem cells with erythroid potential [18][19][20][21][22][23][24]. Figure 5 compares the differential effects of IL-3 and anti-TGF-β on these subpopulations.…”

“…We focused on CD133 + stem cells with erythroid potential, most of which represent a large immature subpopulation of CD34 + cells [18][19][20][21][22][23][24], because our preliminary tests showed them to be more responsive than the remaining CD133 -CD34 + population to neutralizing anti-TGF-β antibodies as well as to the early-acting cytokine interleukin-3 (IL-3). Using a sensitive flow cytometric method that can detect very low levels of cellular globin contents [25,26], we monitored the effects of neutralizing anti-TGF-β antibodies, applied during the first few days of stem cell development, on the subsequent proliferation and globin expression of erythroid progenitors.…”