HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints/Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Servida, F. Articles by Deliliers, G. L. Search for Related Content PubMed PubMed Citation Articles by Servida, F. Articles by Deliliers, G. L.

Functional and Morphological Characterization of Immunomagnetically Selected CD34⁺ Hematopoietic Progenitor Cells

^a Fondazione Matarelli,
^b Centro Trapianti di Midollo and
^c Centro Trasfusionale e di Immunologia dei Trapianti, Ospedale Maggiore, IRCCS, Milan, Italy;
^d Fondazione Maugeri, Pavia, Italy

Key Words. CD34 antigen • Cell separation • Ex vivo expansion • Growth factors • Hematopoietic stem cells • Long-term culture-initiating cells • Ultrastructure

Dr. Davide Soligo, Centro Trapianti di Midollo, Ospedale Maggiore, IRCCS, Via F. Sforza, 35 - 20122 Milan, Italy.

We evaluated the potential of immunomagnetically selected (miniMACS) progenitor cells to give rise to colony-forming cells and their precursors, detected as long-term culture-initiating cells (LTC-IC), as well as their capacity to expand in liquid cultures. A 90% mean purity, a 43.2% yield and a 55.8-fold enrichment were achieved from normal bone marrow. When corrected for enrichment, the mean number of committed progenitor cells and the frequency of LTC-IC (evaluated by means of limiting dilution assay [LDA]) were not statistically different in low density mononuclear cells or in the CD34-enriched fractions. In five cases CD34⁺ selected cells grown in a stroma-free long-term bone marrow culture system with the addition of stem cell factor, interleukin 3, interleukin 6 and GM-CSF every 48 h, showed a 15 (±15) and 31 (±21) mean colony forming unit-granulocyte/macrophage fold increase on cultures at days 7 and 14. However, when corrected for enrichment, the expansion capability of these cells was significantly lower than that of the unseparated fraction, particularly after the first week. Immediately after separation, electron microscopy revealed that the CD34⁺ selected fraction contained more than 45% of well-differentiated myeloid cells (MPO⁺ ), with iron beads preferentially clustered at one pole of the cell surface and sometimes already endocytosed in pinocytic vesicles. After 24 h and 48 h incubation at 37°C, the majority of the cells showed no iron particles, but about 30% of the cells were iron-labeled phagocytic cells. The percentage of apoptotic cells with internalized iron was negligible. These data show that immunomagnetically separated CD34⁺ cells may have a slightly impaired short-term expansion capability, but give rise to both committed and more primitive progenitor cells. During the separation, the iron beads are internalized, rapidly processed in the cytoplasm and do not seem to interfere with in vitro growth.

This article has been cited by other articles:

				N. Forraz, R. Pettengell, and C. P. McGuckin Characterization of a Lineage-Negative Stem-Progenitor Cell Population Optimized for Ex Vivo Expansion and Enriched for LTC-IC Stem Cells, January 1, 2004; 22(1): 100 - 108. [Abstract] [Full Text] [PDF]

				L. Mazini, E. Wunder, H. Sovalat, D. Bourderont, M. Baerenzung, J. Bachorz, and P. Hénon Mature Accessory Cells Influence Long-Term Growth of Human Hematopoietic Progenitors on a Murine Stromal Cell Feeder Layer Stem Cells, November 1, 1998; 16(6): 404 - 412. [Abstract] [Full Text]