Differential response of CD34+ cells isolated from cord blood and bone marrow to MIP-1 alpha and the expression of MIP-1 alpha receptors on these immature cells.
Macrophage inflammatory protein-1 alpha (MIP-1alpha) has been shown to have a role in the control of myeloid stem and progenitor cell proliferation. Recent evidence suggests that MIP-1alpha also has a stimulatory effect on proliferation of mature progenitors as well as an inhibitory effect on immature progenitors in vitro. We have compared the effect of MIP-1alpha on myeloid and erythroid colony formation of CD34+ cells isolated from bone marrow and cord blood. In the presence of MIP-1alpha, bone marrow granulocyte-macrophage-colony forming cells (GM-CFC) were inhibited over a dose range of 15 ng/ml to 500 ng/ml, and GM-CFC from cord blood CD34+ cells were stimulated over the same dose range. MIP-1alpha suppressed BFU-E colonies in both bone marrow and cord blood. Using thymidine suicide assays, the influence of MIP-1alpha on the cycling status of the cells was assessed. A good correlation between the effect of MIP-1alpha on colony formation and cell cycle progression was observed. These results suggest that there is a differential response to MIP-1alpha when bone marrow and cord blood CD34+ cells are compared. Using flow cytometry and a biotinylated human MIP-1alpha/avidin fluorescein conjugate, the expression of MIP-1alpha receptors on CD34+ cells was assessed. The data indicated that there was little quantitative difference in overall expression of receptors (82.9% versus 93%) from bone marrow or cord blood, respectively. However, when Northern blot analysis was used, mRNA for two different MIP-1alpha receptors CCR1 and CCR5 could be detected in bone marrow, but only CCR1 mRNA was seen in cord blood CD34+ samples. Therefore, the expression of different receptor subtypes on CD34+ cells may be responsible for the difference in MIP-1alpha responsiveness observed.
CRC Section of Haemopoietic Cell and Gene Therapeutics, Paterson Institute for Cancer Research, Manchester, United Kingdom.
E A
EA
de Wynter
J
J
Durig
M A
MA
Cross
C M
CM
Heyworth
N G
NG
Testa
D018952:Antigens, CD34 / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D003114:Colony-Forming Units Assay; D004247:DNA / Q000096:biosynthesis; D005312:Fetal Blood / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019402:Macrophage Inflammatory Proteins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D019707:Receptors, Chemokine / Q000032:analysis / Q000096:biosynthesis*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D018952:Antigens, CD34; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger; D019707:Receptors, Chemokine; C080633:macrophage inflammatory protein 1alpha receptor; D004247:DNA