Separation of red blood cell-depleted mononuclear marrow cells by continuous-flow centrifugation using the IBM 2997 blood cell separator—Results of a preclinical study in a dog model

As an alternative technique to density-gradient separation, we studied the preparation of red blood cell (RBC)-depleted marrow mononuclear cells (MNC) by continuous-flow centrifugation (CFC) using the IBM 2997 cell separator in a dog model. Mean recoveries of nucleated and mononuclear cells obtained by this separation technique were 43.1% and 77.7%, respectively, and the mean residual RBC volume was 1.8 mL (1.2% of the RBC volume prior to separation). A mean of 91.4% of marrow progenitor cells were regained in the RBC-depleted fraction. Transplantation of the separated marrow MNC into seven lethally irradiated beagle littermates resulted in complete and durable hematopoietic chimerism. Our results indicate that separation of marrow MNC using an IBM 2997 cell separator is an effective and technically uncomplicated alternative to gradient medium separation.