Selection and characterization of early hematopoietic progenitors using an anti-CD71/S06 immunotoxin.
Exp Hematol
; 22(2): 166-73, 1994 Feb.
Article
em En
| MEDLINE
| ID: mdl-7507858
ABSTRACT
Most recently reported methods to select early hematopoietic cells basically rely on the depletion of committed progenitors. This task is generally accomplished by laborious procedures, which are sometimes difficult to reproduce. To simplify the selection method, we took advantage of the expression of the transferrin receptor (CD71) by proliferating committed progenitors and the lack of CD71 on noncycling immature progenitors. A monoclonal antibody (MAB) reactive with CD71 has been conjugated to the Saponaria officinalis seed ribosome-inactivating protein (SO6). The immunotoxin (IT) complex was used at increasing concentrations on normal non-phagocytizing bone marrow cells. A complete and reproducible killing effect on myeloid (colony-forming unit-granulocyte/macrophage [CFU-GM]) and erythroid (burst-forming unit-erythroid [BFU-E]) progenitors was observed for IT concentrations of 1 x 10(-7) M. Unconjugated SO6 or anti-CD71 MAB had no effect on cell growth and viability. IT-resistant cells were able to generate CFU-GM after 7, 14, and 21 days of suspension culture in the presence of 5637 CM. Maximal CFU-GM values were obtained at day 21 and nearly approached the pretreatment values (mean 2587 vs. 3877 CFU-GM/mL). Growth factor enhancement of CFU-GM yield was obtained only by stem cell factor (SCF) at day 7; SCF, as well as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), had an enhancing effect at days 14 and 21. IT toxicity on highly immature progenitors was ruled out by evaluating the growth of long-term culture-initiating cells (LTC-IC) from IT-treated cultures. LTC-IC frequency was found to be 1 out of 1506 seeded cells, which is within the range of normal untreated BM cells. In conclusion, anti-CD71 IT allows a simple and complete depletion of committed progenitors while sparing immature hematopoietic cells. The high CD71 expression by leukemic cells makes the procedure potentially suitable for in vitro purging.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Células-Tronco Hematopoéticas
/
Antígenos de Diferenciação de Linfócitos B
/
Antígenos CD
/
Separação Celular
/
Imunotoxinas
/
N-Glicosil Hidrolases
Idioma:
En
Revista:
Exp Hematol
Ano de publicação:
1994
Tipo de documento:
Article
País de afiliação:
Itália