| Description |
NK cells are not a homogeneous cell population and can be divided into several subsets according to functional and phenotypic differences. The CD56+CD8+/CD8– NK Isolation Kit was developed to enrich two NK cell populations: CD3–CD56+CD8+ and CD3–CD56+CD8– NK cells. CD3–CD56+CD8+ NK cells represent approximately 3% and CD3–CD56+CD8– NK cells about 4% of all PBMCs in healthy donors. Both NK cell populations differ in the presence of homodimeric CD8 formed by two α-chains. Recently, the expression of CD8α/α on CD3– NK cells revealed to be of fundamental significance, as the CD3–CD56+CD8+ subset was shown to have a stronger cytotoxic function compared to its CD8– counterpart.1
The isolation of both CD56+CD8+ and/or CD56+CD8– NK cell subsets is performed in a two-step procedure. In both cases, non-NK cells, i.e., T cells, B cells, dendritic cells, stem cells, monocytes, granulocytes, and erythroid cells are first indirectly magnetically labeled with a cocktail of biotin-conjugated antibodies against lineage-specific antigens and a cocktail of MicroBeads. Upon subsequent magnetic separation of the cells over a MACS® Column, the magnetically labeled non-NK cells are retained within the column, while the unlabeled NK cells run through. In the second step, the pre-enriched NK cells are directly labeled with CD8 MicroBeads. Upon subsequent magnetic separation, either the non-labeled CD56+CD8– NK cells (LD Column), or the labeled CD56+CD8+ NK cells (MS Column) are isolated. For isolation of both subsets from one sample, the flow-through fraction of the MS Column is further separated over an LD Column. |
| Applications |
| The CD56+CD8+/CD8– NK Isolation Kit was developed for specific isolation of CD56+CD8+ and CD56+CD8– NK cells from PBMCs, for example, for phenotypical and functional characterization of NK cell subsets, for the analysis of receptor expression, cytokine secretion, or cell-cell interaction with other cells of the innate and adaptive immune system. Isolated NK cells are also used to study the role of NK cells in diseases, e.g., hepatitis infection or cancer, as well as during pregnancy. |
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| Figure 1 |
| The CD56+CD8+ and CD56+CD8– NK cell subsets were isolated from human PBMCs using the CD56+CD8+/CD8– NK Cell Isolation Kit. Non-NK cells were depleted using an LS Column. The enriched NK cells were magnetically labeled with CD8 MicroBeads, and CD56+CD8+ NK cells were isolated by positive selection using an MS Column. For isolation of the CD56+CD8– NK cells, the wash and the flow-through fraction of the MS Column were further separated using an LD Column and collected in the flow-through. Cells were fluorescently stained with CD8-PE and CD56-APC. |
| A: PBMCs before separation |
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| B: Pre-enriched NK cells after depletion of non-NK cells |
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| C: Isolated CD56+CD8+ NK cells |
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| D: Isolated CD56+CD8– NK cells |
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