P-Selectin coated microtube for enrichment of CD34+ hematopoietic stem and progenitor cells from human bone marrow.

BACKGROUND Enrichment and purification of hematopoietic stem and progenitor cells (HSPCs) is important in transplantation therapies for hematologic disorders and in basic stem cell research. Primitive CD34+ HSPCs have demonstrated stronger rolling adhesion on selectins than mature CD34- mononuclear cells (MNCs). We have exploited this differential rolling behavior to capture and purify HSPCs from bone marrow by perfusing MNCs through selectin-coated microtubes. METHODS Bone marrow MNCs were perfused through the cell-capture microtubes coated with adhesion molecules. We washed the device lumen and visualized and estimated captured cells by video microscopy. Adherent cells were eluted by high shear, calcium-free buffer, and air embolism. We used immunofluorescence staining followed by flow cytometry to analyze CD34+ HSPCs. RESULTS CD34+ HSPC purity of cells captured in adhesion molecule-coated devices was significantly higher than the fraction of CD34+ cells found in bone marrow MNCs [mean (SE) 2.5% (0.8%)]. P-selectin-coated surfaces yielded 16% to 20% CD34+ cell purity, whereas antibody-coated surfaces yielded 12% to 18%. Although CD34+ cell purity was comparable between selectin and antibody surfaces, the total number of CD34+ HSPCs captured was significantly higher in P-selectin devices (approximately 5.7 x 10(4) to 7.1 x 10(4)) than antibody devices (approximately 1.74 x 10(4) to 2.61 x 10(4)). CONCLUSIONS P-selectin can be used in a compact flow device to capture HSPCs. Selectin-mediated capture of CD34+ HSPCs resulted in enrichment approximately 8-fold higher than the CD34+ cell population from bone marrow MNCs. This study supports the hypothesis that flow-based, adhesion molecule-mediated capture may be a viable alternative approach to the capture and purification of HSPCs.