Abstract Immunomagnetic enrichment of leukocytes is an important technique in both research and clinical applications. Accordingly, there is a continuous need for improved, reliable cell separation methods. Current enrichment strategies using magnetic labeling of the target cells allow for highly efficient isolation, but in some instances removal of residual cell surface labeling after isolation is of high interest. To this end, we have combined the benefits of positive selection by MACS® Technology, the proven state-of-the-art method for the isolation of functional, viable cells, with a novel technology enabling the removal of both superparamagnetic beads and antibody fragments. REAlease™ Technology provides an easy and fast solution for the highly specific isolation of unlabeled leukocytes directly from PBMCs. We present our latest results on cell separation with REAlease Technology based on key human immune cell markers, i.e., CD3, CD4, CD8, CD19, and CD56. The benefits of these releasable labels are demonstrated for the isolation of important subsets such as CD3−CD56+ NK cells, and CD4+ and CD8+ cell populations from a single sample. Using various assays, we show that functionality and viability of the target cells are preserved without cell activation.

Immunomagnetic enrichment of leukocytes plays an important role in both research and clinical applications. Accordingly, there is a continued need for improved and reliable cell separation methods. Current enrichment strategies with specific magnetic labeling of the target cells allow for efficient isolation but have the disadvantage of residual labeling on the cell surface after isolation. Therefore, the isolation of viable cells with a minimal potential of surface-initiated activation becomes increasingly more important. To this end, we have combined magnetic cells separation, MACSTM, the proven state-of-the-art method for the isolation of viable cells from heterogeneous cell populations with a releasable-label technology developed at Miltenyi Biotec, which allows direct isolation of truly unmarked cells. This method provides an easy and fast solution for the highly specific separation of unlabeled leukocytes directly from PBMCs. In this poster we present our latest results from this novel technology applied to key markers in the immunology field.

Regulatory T cells (Tregs) play a pivotal role in maintaining peripheral tolerance of unspecific or excessive immune responses. Therefore, the enrichment of these cells and their cultivation is of great interest for basic and translational research. Accordingly, there is a considerable need for continually improved and reliable cell isolation protocols. We introduce here a rapid, easy, and convenient strategy for the isolation of regulatory T cells directly from anticoagulated whole blood without the need for density gradient centrifugation. The new immunomagnetic separation protocol provides an easy and fast solution for the highly specific isolation of CD4+ CD25highCD127− regulatory T cells directly from whole blood within 30 minutes ready for downstream application such as flow cytometric phenotyping, gene expression studies, cytokine analysis, suppression assays, or cell expansion. The procedure, leads to populations of CD4+ CD25highCD127− cells with high yields (2×104/mL whole blood), purities (>90%) and viability (>98%) as proven by flow cytometric analysis. In addition, enriched Tregs were capable for in vitro expansion for several weeks while remaining stable FoxP3 expression.