CD19 is a 95kDa, type I transmembrane glycoprotein member of the immunoglobin superfamily. It is expressed by B cells and follicular dendritic cells and regulates B-lineage commitment during hematopoietic stem cell differentiation. 6%-23% human PBMC are CD19 positive. Human CD19 Magnetic Beads Kit can be used for isolation or depletion of human CD19 B lymphocytes from PBMC, whole blood, or other sample types. Following incubation with biotinylated human CD19 antibody and Streptavidin magnetic beads, the cell sample is placed on a magnet. CD19+ cells remain attached to magnetic beads after separation and can be used for downstream applications, such as in expansion of cells, but are not suitable for flow cytometry analysis. CD19- cells remain in supernatant and can also be used for further applications.