Human-CD19/GFP Stable Cell Line - K562

CD19 is a transmembrane glycoprotein belonging to the immunoglobulin superfamily, expressed exclusively on the surface of B cells from early development through maturation. It serves as a critical co-receptor for the B cell receptor complex, modulating signaling thresholds essential for B cell activation and differentiation. Because of its restricted expression pattern on normal B cells and its retention on malignant B cells in diseases such as acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma, CD19 has become one of the most clinically validated targets in cancer immunotherapy. The Human-CD19/GFP Stable Cell Line - K562 is generated by stably transducing the human chronic myeloid leukemia cell line K562 with a lentiviral vector encoding full-length human CD19 along with a green fluorescent protein (GFP) reporter. K562 cells are naturally CD19-negative, which makes them an ideal parental background for this construct. The co-expression of CD19 and GFP enables direct visual confirmation of transgene expression by fluorescence microscopy or flow cytometry, and the stable integration ensures consistent, long-term antigen presentation across multiple passages without the need for continuous drug selection.

This cell line is primarily designed for the development, optimization, and quality control of CD19-directed immunotherapies. It serves as a reliable target cell population for evaluating the binding specificity and affinity of anti-CD19 monoclonal antibodies, bispecific T cell engagers (BiTEs), and chimeric antigen receptor (CAR) constructs. In co-culture cytotoxicity assays, the CD19-expressing K562 cells can be co-incubated with anti-CD19 CAR-T or CAR-NK effector cells, and target cell killing can be monitored through GFP signal loss or by adding exogenous labeling reagents. The GFP reporter also facilitates real-time tracking of target cell fate in antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) assays. Additionally, researchers can use this cell line as a positive control for flow cytometry panel setup, for evaluating CD19-specific internalization kinetics, or as a tool to assess the potential off-target effects of novel CD19-directed therapeutics.