Comparison Of Two Immunomagnetic Separation Technologies To Deplete T Cells From Human Blood Samples

The objective of this study was to compare the performance of two immunomagnetic separation technologies to deplete T cells from buffy coats of human blood. Specifically, two versions of the commercial MACS® Technology: MiniMACS and SuperMACS, and a prototype, flow‐through system, the QMS, were evaluated. Peripheral blood mononuclear leukocytes (PBL) were isolated from buffy coats and an immunomagnetic separation of CD3+ cells was conducted using company and optimized labeling protocols. To mimic peripheral blood containing bone marrow purged hematopoietic stem cells, HSC, CD34 expressing‐cells (KG1a) were spiked into PBL prior to T‐cell depletion once optimized depletion conditions were determined. Once the labeling protocol was optimized, the MiniMACS system performed well by producing a highly enriched CD3+ fraction, and a respectable level of depletion of T cells and recovery of KG1a cells in the depleted fraction; an average log10 depletion of T cells of 2.88 ± 0.17 and an average recovery of the KG1a cells of 60.8 ± 5.94% (n = 14). The performance of the SuperMACS system was very similar with an average log10 depletion of T cells of 2.89 ± 0.22 and an average recovery of KG1a of 63.1 ± 8.55% (n = 10). In contrast, the QMS system produced an average log10 depletion of T cells of 3.98 ± 0.33 (n = 16) with a corresponding average recovery of 57.9 ± 16.6% of the spiked CD34+ cells. The aforementioned QMS performance values were obtained using sorting speeds ranging from 2.5 × 104 to 1.7 × 105 cells per second. It is suggested that the lack of a 100% recovery of the unlabeled KG1a cells is the result of a previously reported “drafting” phenomena which pulls unlabeled cells in the direction of the magnetically labeled cells thereby resulting in loss of the unlabeled cells. © 2006 Wiley Periodicals, Inc.