This product is a FCM antibody cocktail made up of FITC Anti-Human CD3 Antibody [Clone: OKT-3] (Mouse IgG2a, κ) and PE Anti-Human CD19 Antibody [Clone: CB19] (Mouse IgG1, κ).CD3 is a heterotetrameric protein consisting of a CD3Œ≥, a CDŒ¥ and 2 CD3Œµ. It forms complex with TCR. OKT-3 recognize human CD3Œµ. Human CD3 is expressed on the surface of T cells and NKT cells.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.