This product is a FCM antibody cocktail made up of FITC Anti-Human CD19 [Clone: CB19] (Mouse IgG1, κ), PE Anti-Human CD56 Antibody [Clone: 5.1H11] (Mouse IgG1, κ), PE/Cyanine7 Anti-Human CD3 Antibody [Clone: OKT-3] (Mouse IgG2a, κ) and PerCP Anti-Human CD45 Antibody [Clone: HI30] (Mouse IgG1, κ).; CD19 is a single-chain transmembrane glycoprotein expressed on B cells of all stages except plasma cells. It is a common marker for B cells. CD19 is also expressed in follicular dendritic cells. It forms complex with CD21 and CD84, which forms co-receptor with BCR. It takes part in B cell development, activantion and differentiation.; CD56 is also call neural cell adhesion molecule (NCAM), expressed on neurons, glia and skeletal muscle cells. In hematopoietic cells, CD56 is also expressed on NK cells and NKT cells. CD56 can be used to detect NK cells, γ/δ T cells and activated CD8+ cells.; CD3 is a heterotetrameric protein consisting of a CD3γ, a CDδ and 2 CD3ε. It forms complex with TCR. OKT-3 recognize human CD3ε. Human CD3 is expressed on the surface of T cells and NKT cells.; CD45 is a single-chain type I transmembrane glycoprotein. Except for erythrocytes and platelets, CD45 is expressed on nearly all of the hematopoietic cells with high level. It is a common marker for blood leukocytes. CD45 is a receptor type protein tyrosine phophatase and plays essential roles in B cell and T cells signaling.