Isolation and Cryogenic Preservation of Monocytes from Plateletpheresis Cellular Residues.

Abstract : Human monocytes were isolated from the cellular residues afte plateletpheresis of donars using the Haemonetics Model 30 Blood Cell Processor. Mononuclear cells were obtained with Ficoll-Isopaque and separated from lymphocytes by stepwise elutriation in a Beckman JE-6 rotor equipped with two isolation chambers. The isolated cells were frozen in a solution containing an extracellular (dimethylsulfoxide, DMSO) cryoprotective compound. In three procedures, approximately 1 x 10 to the 9th power monocytes were obtained. Ninety-nine percent of isolated monocytes were viable in the fluorescein diacetate (FDA)-ethidium bromide (EB) test. Myeloperoxidase-positive cells were 95% and 90% respectively in Chambers nos. 1 and 2. Ninety-four percent of monocytes ingested 5 or more opsonized Fluolite particles and 95% ingested 1 or more ethidium-treated zymosan particles. After storage in liquid nitrogen for up to 9 weeks, 99% of the cells were recovered after thawing. Of these, 95% were myeloperoxidase-positive, 94% showed intact memranes in the FDA-EB test, 95% ingested 5 or more opsonized Fluolite particles, an 96% ingested 1 or more ethidium-treated xymosan particles.