RosetteSep Human B Enrichment, 2 mL

Designed to enrich B cells from whole blood by negative selection, the RosetteSep™ Human B Cell Enrichment Cocktail from STEMCELL Technologies leaves the target cells untouched. Supplied in a 2 mL format intended for labeling 40 mL of whole blood, the cocktail contains a combination of monoclonal antibodies assembled into bispecific Tetrameric Antibody Complexes (TACs) directed against cell surface antigens on non-B cells. These complexes crosslink unwanted cells to red blood cells (RBCs), forming immunorosettes that pellet with free RBCs during standard density gradient centrifugation, while the desired B cells are collected as an enriched population at the plasma/density gradient interface. Compatible density gradient media include Lymphoprep™, RosetteSep™ DM-L, and Ficoll-Paque™ PLUS, and the workflow can be combined with SepMate™ PBMC isolation tubes.

The protocol uses 50 μL of cocktail per mL of whole blood, with a 20-minute room temperature (15 - 25°C) incubation, followed by dilution with PBS + 2% FBS and layering over density gradient medium. Centrifugation is performed for 20 minutes at 1200 x g with the brake off, after which enriched cells are washed with PBS + 2% FBS; optional Ammonium Chloride lysis can be used to remove residual RBCs. In a typical enrichment profile, a starting sample containing 6% CD19+ cells yields an enriched fraction of 81% CD19+ cells with 53% recovery. Across 31 measurements (mean ± 1 SD), purity is 83 ± 8% CD19+ cells and recovery is 71 ± 39% CD19+ cells, with FACS histograms typically showing 81% - 83% CD19+ content. Purity can be assessed by flow cytometry using Anti-Human CD19 (Clone HIB19) or Anti-Human CD20 (Clone 2H7) antibodies. The product is stored at 2 - 8°C, should not be frozen, and is manufactured under an ISO 13485-certified quality management system. For research use only; not intended for human or animal diagnostic or therapeutic uses.