Firefly Luciferase CD19/CD22 Double Knockout Raji Cell Line

Firefly Luciferase CD19/CD22 Double Knockout Raji Cell Line is a Raji cell line in which CD19 (Cluster of Differentiation 19, B lymphocyte surface antigen B4, or CVID3) and CD22 (Cluster of Differentiation 22, or SIGLEC2) are not expressed due to CRISPR/Cas9 genome editing, while firefly (Photinus pyralis) luciferase is constitutively expressed under the control of an EF1a promoter. This cell line was generated by transfection of the CD19/CD22 Double Knockout Raji Cell Line (BPS Bioscience #82956) with Firefly Luciferase Lentivirus (EF1a Promoter, Puromycin) (BPS Bioscience #78740-P). This cell line has been validated by genome sequencing, flow cytometry, and luciferase activity measurements. The Raji cell line was established from a Burkitt's lymphoma patient. Raji cells constitutively express the B cell antigens CD19, CD20, and CD22, and offer a physiologically relevant platform to evaluate cancer-directed immunotherapies such as Chimeric Antigen Receptor (CAR) T or CAR-NK cells. CD19 (also known as Cluster of Differentiation 19, B-lymphocyte surface antigen B4, or CVID3) is a glycoprotein expressed on the surface of B lymphocytes through most phases of B cell maturation. It is strictly required for B cell terminal differentiation. Mutations in the CD19 gene cause severe immune-deficiency syndromes associated with impaired antibody production, such as CVID3 (common variable immuno-deficiency 3). The majority of B cell malignancies express normal to high levels of CD19, making it a nearly ideal target for cancer immunotherapy. Blinatumomab, a CD19/CD3 bi-specific T cell engager (BiTE) has been approved for relapsed/refractory B precursor ALL (Acute lymphoblastic leukemia) and CD19 was the target of the first approved CAR-T cell therapy. Studies of CD19 function and expression profiles will continue to broaden our knowledge and support broader applications in cancer therapy. CD22 (also known as Siglec-2) is expressed on the membrane of B-cells. CD22 regulates the B-cell immune response by acting as an inhibitory co-receptor of the B-cell receptor, shown to influence B-cell receptor signaling as well as B-cell survival and migration. CD22 is expressed on the cell surface of most B-cell malignancies and can serve as a B-cell-specific target for cancer immunotherapies. One area of interest is in developing CD22-targeting antibody-drug conjugates, as CD22 is frequently endocytosed from the cell membrane. In 2017, the FDA approved Besponsa (inotuzumab ozogamicin), an antibody-drug conjugate targeting CD22, for patients with B-cell acute lymphoblastic leukemia (B-ALL). Additional therapies targeting CD22 are under evaluation. In particular, bispecific CAR-T cells targeting CD19 and CD22 are being investigated for the potential to increase cancer treatment efficacy while reducing the chance of relapse due to antigen escape. Firefly luciferase has been used as a sensitive reporter to study a wide range of biological responses. The signal generated by the firefly luciferase reporter is proportional to Raji cell numbers and facilitates the quantification of Raji cells killing upon co-culture with CAR-T or NK cells.