A system for obtaining large numbers of cryopreserved human monocytes purified by leukapheresis and counter-current centrifugation elutriation (CCE).

A system has been developed for the isolation of large numbers of unfractionated mononuclear cells from single, well characterized normal individuals and for the separation by elutriation of these cells into populations of greater than 90% pure monocytes and greater than 99% pure lymphocytes. The total number of monocytes obtained from a single donor averaged about 550 million. After cryopreservation and thawing of these cells, the viability remained greater than 90%, 80% of original cells were recovered, and the ability to ingest antibody-coated targets was comparable to that of fresh monocytes. The cells remained sterile without the use of antibiotics and were suitable for long-term culture. The monocytes that were isolated and cryopreserved by these procedures functioned reproducibly as inhibitors of tumor cell growth and in an assay of responsiveness to monocyte migration inhibitory factor (MIF).