Use of the CS-3000 Plus to prepare apheresed blood cells for immunomagnetic positive cell selection

The Baxter CS-3000 Plus Blood Cell Separator was used to prepare progenitor cell components in a three-step process. The process was designed to remove platelets and plasma from a leukapheresis cell product before incubation with anti-CD34 monoclonal antibody (9C5) and to remove unbound monoclonal antibody after incubation. Fluorochrome-labeled cultured KG1a (CD34+) cells were added to the leukapheresis cell product (at 2% of total WBC) before CS-3000 processing to evaluate the CS-3000 process for preparing cells for immunomagnetic selection using the Isolex 300 (SA) Magnetic Separation system. Data were obtained using five leukapheresis products. Two percent of the nucleated cells were lost during the platelet reduction wash, and 67% of the platelets were removed. The amount of antibody initially added to the cells for incubation ranged from 3.9 to 7 mg (0.5 microgram/10(6) nucleated cells). The residual antibody in the cells after the antibody wash ranged from 11 to 40 micrograms. The antibody wash resulted in a 3% loss of nucleated cells and an additional 66% removal of platelets. The antibody-sensitized cells were then processed on the Isolex 300 (SA) system. The purity and yield of the Isolex KG1a cell product were 94% and 82%, respectively.