Comparison of MACS and FACS Sorting of Sca-1+ Cells from Mouse Bone Marrow

Cell based therapies offer a possible solution to some currently disastrous diseases. Some of the cells with a promising future for therapeutic use are biologically very rare, such as Hematopoietic Stem Cells (HSCs) and Endothelial Progenitor Cells (EPCs) which make up less than 1% of human bone marrow or peripheral blood. HSCs are marked with Stem cell antigen-1 (Sca-1) and are currently being used therapeutically to treat leukemia, lymphoma, and blood disorders. EPCs are able to regenerate blood vessels and are, therefore, hypothesized to be an effective treatment for many cardiovascular diseases. Effective and affordable isolation of these rare cell populations is necessary for new cell based therapies to be transitioned into clinical use. Of the two widely used antigen positive isolation techniques Magnetic Activated Cell Sorting (MACS) and Fluorescence Activated Cell Sorting (FACS), neither offers both high throughput and high purity sorting. However, a technique in development called Antigen Specific Lysis (ASL) is hypothesized to achieve these two criteria. This technique isolates cells by encapsulating the target population in a hydrogel, which also protects the target cell from lysis in hypotonic solutions. With the hope of comparing the three antigen positive cell sorting techniques for rare cell isolations, we first aimed to isolate Sca1+ cells from the bone marrow of mice using MACS and FACS. The cells isolated with these two techniques were compared for purity, recovery, and enrichment. We also compared the viability of the enriched cell samples and the amount of time it would take to sort a therapeutic dose of cells using each technique. Overall, the purity, recovery, and fold enrichment for FACS was higher than that of MACS. However, the time it would take to sort a therapeutic dose of EPCs from FACS is much longer than that for MACS. In our following study, we will be isolating Sca1+ cells by hydrogel encapsulation using ASL and compare the method against MACS and FACS.

Research Supported by the National Science Foundation REU Program #EED-1460486