Isolation of large numbers of highly purified lymphocytes and monocytes with a modified centrifugal elutriation technique.

A modified centrifugal elutriation technique is described for the isolation of large numbers of lymphocytes and monocytes. Elutriation was carried out by lowering the rotor speed at a constant flow rate which was generated by hydrostatic pressure. The flow rate could be kept constant if the separation procedure was performed at high pressure and high systemic resistance. Up to 2.3 X 10(9) mononuclear cells derived from 2000 ml blood were separated in one single experiment in approximately 1 h. The lymphocytes and monocytes were isolated at purities of 98 +/- 1% and 94 +/- 1% respectively. The purity of the lymphocytes was increased to 99.8 +/- 0.1% by a second elutriation run. Additional advantages of the elutriation procedures are that the choice of medium is free, and that relatively large numbers of cells may be separated with high recoveries.