The effect of recombinant human stem cell factor and basic fibroblast growth factor on the in vitro radiosensitivity of CD34+ hematopoietic progenitors from human umbilical cord blood.
Human umbilical cord blood (CB) cells selected by immunomagnetic beads for expression of the CD34 antigen were irradiated with increasing doses of x-rays (72 cGy/min). Clonogenic survival of the hematopoietic progenitors, including mixed colony-forming cells (Mix-CFC), erythroid burst-forming units (BFU-E), and granulocyte-macrophage colony-forming cells (GM-CFC), was determined in methylcellulose cultures containing placenta conditioned medium (PCM) and erythropoietin (Epo). Exponential survival curves were fitted to the data of all the colonies, resulting in D0 = 95 cGy for Mix-CFC, 136 cGy for BFU-E, and 136 cGy for GM-CFC. Additionally, the radiosensitivity of CD34+ cells was studied employing cultures containing either recombinant human stem cell factor (rhSCF) or basic fibroblast growth factor (b-FGF) in combination with PCM and Epo. It was found that the colony-forming efficiency (CFE) of non-irradiated CD34+ cells of 5.5% (range 1.4 to 14.4%) did not increase after the addition of SCF or b-FGF to the culture. The radiation response characteristics showed, however, that in the presence of SCF, the D0 value and the extrapolation number n increased significantly. This suggests the stimulation of what operationally is termed "recovery from potentially lethal damage." In contrast, no response modifying effect could be seen for b-FGF.
Kreja
L
L
Institute for Occupational and Social Medicine, University of Ulm, Germany.
Thoma
S
S
Selig
C
C
Lamping
C
C
Ziegler
B L
BL
Nothdurft
W
W
D015703:Antigens, CD / Q000097:blood*; D018952:Antigens, CD34; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004921:Erythropoietin / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000276:immunology / Q000528:radiation effects*; D006801:Humans; D007231:Infant, Newborn; D011836:Radiation Tolerance; D011994:Recombinant Proteins / Q000494:pharmacology; D019089:Stem Cell Factor
D015703:Antigens, CD; D018952:Antigens, CD34; D017077:Culture Media, Conditioned; D016298:Hematopoietic Cell Growth Factors; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D016222:Fibroblast Growth Factor 2; D004921:Erythropoietin