Table 1.

Effect of subpopulation enrichment/depletion on colony-forming unit endothelial progenitor cells (CFU-EPCs) in mononuclear cell (MNC) populations

Source	Number of CFU-EPCs per 10⁶ MNCs plated
Unfractioned MNCs^*	21
2-h adherent cells (> 80% CD14+)^*	25
2-h non-adherent cells^*	2
CD14-enriched (> 98%)^*	41
CD14-depleted^*	0
CD34-enriched (> 90%)^†	0
CD34-depleted^†	3
CD133-enriched (> 90%)^†	0
CD133-depleted^†	8

CFU-EPCs are slightly increased when normal peripheral blood MNCs are enriched for monocytes (to about 80% CD14+) by 2 h of adherence on uncoated culture plates. Further enrichment of monocytes (to 98%) by CD14+ selection by fluorescence-activated cell sorting further increased CFU-EPCs and completely removed CFU-EPCs from the CD14-depleted plastic-adherent cells. CFU-EPCs were not found in CD34-enriched (> 90%) or CD133-enriched (> 90%) MNCs from different HPC-rich cell sources. Their depleted column eluates tend to show reduced CFU-EPC activity as compared with the unfractioned starting MNCs, which may imply some loss of CFU-EPC activity by retention on columns by adhesion, implying these cells are adherent.

Paired normal peripheral blood samples (n = 6).

^†

Unpaired HPC-rich samples (bone marrow, cord blood, mobilized blood).