Here's a protocol for isolating peripheral blood mononuclear cells from whole blood.The peripheral
blood mononuclear cells are *mainly* lymphocytes and monocytes. To isolate them you spin whole
blood or blood from which you've removed plasma on top of a layer of 15ml of Ficoll reagent. Ficoll
reagent is a highly branched sucrose polymer that does not penetrate biological membranes.
the blood is first diluted with phosphate buffered saline. The ratio that you use
is one part PBS to one part blood. the diluted blood is then placed on top of the
Ficoll and then you spin it at 1200 xg for 10min (when using Sepmate tube). You must reduce the
speed and extend the time of spinning if you are centrifuging without the aid of a Sepmate
tube. Once spun, the supernatant contains the peripheral blood mononuclear cells (PBMCs).