To begin, add eight milliliters of DPBS into a sterile 50 milliliter conical tube. To this, add eight milliliters of blood and use a three milliliter plastic Pasteur pipette to mix the contents well. Add 15 milliliters of lymphocyte isolation medium into another conical tube.
Tilt the tube by 20 to 30 degrees. Then use a three milliliter Pasteur pipette to apply the first layer of the blood DPBS mix gently over the isolation medium. Layer the remaining mixture carefully over the sidewall of the tube.
Slowly bring the tube into an upright position to layer the remaining blood onto the blood layer. Centrifuge the tube at 1000G for 10 minutes at room temperature in a swinging bucket with the brakes off. The blood PBMC mix will separate into four distinct layers.
With a Pasteur pipette, remove two thirds of the plasma layer, then use a one milliliter pipette to collect the PBMCs. Transfer the PBMCs into a new 50 milliliter tube until the entire layer has been harvested. Then make the volume up to 25 milliliters with DPBS to remove residual isolation medium and other residues.
Centrifuge the tube at 100G for 10 minutes at room temperature with the brakes on. Then remove the supernatant with a vacuum pump. Next, resuspend the pellet in one milliliter DPBS and add more DPBS to make up the volume to 25 milliliters to wash and resuspend the pellet.
Cool a freezing container to four degrees celsius. Then place fetal bovine serum on ice. Resuspend the cell pellet containing the isolated PBMCs in one milliliter of fetal bovine serum.
Next mixed DMSO with cooled serum on ice at a ratio of one to five. Transfer the cell suspension to two milliliter labeled cryotubes, using one tube per collection tube. With an automated cell counter, determine the cell count and viability.
Use a one milliliter pipette to drop one milliliter of the DMSOFBS mixture into the tube. Then place the tubes in the pre-cooled freezing container. Place the container in a freezer at minus 80 degrees Celsius for 24 hours.
The next day, remove the tubes from the freezer and store them in the gas phase of liquid nitrogen. Cell counts and viability were consistent before and after cryo-preservation indicating successful isolation and preservation.
