Cells were purified to more than 95% purity as assessed by morphology and flow cytometry. After cell isolation, an aliquot of purified cells was removed and assessed for purity as described. Example of CD19⁺ B cells isolated from peripheral blood mononuclear cells. (A) Peripheral blood mononuclear cells assessed by Romanovsky-stained cytocentrifuge preparations and (B) phycoerythrin-labeled anti-CD19 by flow cytometry. After purification, more than 98% of cells were CD19⁺ as assessed by (C) a 1000 differential cell count of Romanovsky-stained cytocentrifuge preparations and (D) flow cytometry. Images and purity levels are representative of all samples processed. (A,C) Romanovsky-stained samples were visualized using an Olympus BX51 microscope (Olympus, Tokyo, Japan) with a 100×/1.30 oil objective and immersion oil (nd 1.516; Olympus). Images were captured using a Pixera Pro600ES and Penguin/Pro Application Suite version 3.0.1 (Pixera, Los Gatos, CA).