PBMC - Peripheral Blood Mononuclear Cell
A peripheral blood mononuclear cell (PBMC) is a blood cell with a single, round nucleus. The term "peripheral" refers to mature blood cells that are not located in blood-forming organs such as the bone marrow, but circulate in the peripheral blood. The main components of peripheral blood include blood plasma, which serves as a transport medium, as well as red blood cells (Erythrozyten), white blood cells (Leukozyten) and blood platelets (Thrombocytes).
PBMCs, sometimes referred to as PMNCs (peripheral mononuclear cells) or MNCs (mononuclear cells), comprise all mononuclear leukocytes. These include:
- Lymphocytes (T-cells, B-cells, NK-cells)
- Monocytes
- Dendritic Cells and
- Basophilic Granulocytes.
Isolation / enrichment of PBMC by density gradient centrifugation
The term PBMC (peripheral blood mononuclear cells) is closely associated with the isolation of cells from whole blood through a Density gradient centrifugation.
Polymorphonuclear leukocytes (with multiple segmented nuclei), such as granulocytes, are depleted in this fraction. Neutrophil and eosinophil granulocytes cannot be enriched from a PBMC fraction prepared by standard density gradient separation (the medium has a density of 1.077 g/ml). Basophilic granulocytes differ in density and can be partially found in the PBMC fraction. Erythrocytes are strongly reduced compared to the initial cell count.
The density gradient-enriched PBMCs are sometimes referred to as buffy coat. In this context, buffy coat describes the layer of enriched leukocytes in the interphase.
First, a synthetic polymer solution with a defined density is overlaid with blood or sample material. After preparation, a centrifugation step takes place. In the interphase between the two solutions, the cells accumulate at the corresponding density. The interphase containing the PBMCs is carefully removed. The enriched mononuclear cells are then washed and used for further application.
Isolation / enrichment of PBMC with PBMC Spin Medium
Das whole blood is carefully overlayed to the PBMC Spin Medium (2), welches in einem Zentrifugenröhrchen vorgelegt wird, gegeben. Dabei ist darauf zu achten, dass sich die beiden Flüssigkeiten nicht miteinander vermischen. Alternativ können pluriMate Röhrchen verwendet werden. Die pluriMate Barriere erleichtert das Überschichten und verhindert die Vermischung von Probenmaterial mit dem Dichtemedium.
Fig. 1: PBMC preparation with PBMC Spin Medium. The sample material (1) is carefully overlayed on the density medium (2).
In the following centrifugation step, the actual density gradient centrifugationthe sample is separated into the different layers. The mononuclear cells (2) are enriched between the plasma (1) and the density medium (3).
