Polymorphprep

Isolation of human polymorphonuclear cells

With the exception of the basophils, polymorphonuclear leukocytes (PMNs) have a much greater buoyant density than the mononuclear cells, >1.085 g/ml. Unfortunately, the buoyant density of the erythrocytes tends to be from 1.09 – 1.11 g/ml, this makes a separation from whole blood using a density barrier similar to that used for mononuclear cells more difficult.
A number of procedures have been developed in an effort to overcome these difficulties.

The high osmolality of Polymorphprep causes erythrocytes to lose water and shrink, thus increasing their effective buoyant densities. This allows the dextran aggregated erythrocytes to sediment rapidly through the dense medium.

Because the osmotic gradient between the medium and the erythrocytes declines as the cells sediment further into the medium (ie the water loss from the erythrocytes is greatest at the top of the Polymorphprep and progressively decreases as they sediment further) – a gradient of diatrizoate forms within the density barrier. The PMNs band is within this density gradient while the mononuclear cells remain at the sample/medium interface.

Each batch of Polymorphprep is checked on the level of endotoxins using a specific LAL test. Our goal is to produce batches with an endotoxin level lower or equal to 0.13 IU/ml.