Firefly Luciferase CD22 Knockout Raji Cell Line

Firefly Luciferase CD22 Knockout Raji Cell Line is a Raji cell line in which CD22 (Cluster of Differentiation 22, or SIGLEC2) is not expressed due to CRISPR/Cas9 genome editing. These cells also constitutively express firefly (Photinus pyralis) luciferase under the control of an EF1a promoter. This cell line was generated by transduction of the CD22 Knockout Raji Cell Line (BPS Bioscience #82970), which was created by electroporation with Cas9-sgRNA ribonucleoprotein complexes containing sgRNAs, 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 measurement. The Raji cell line was established from a Burkitt's lymphoma patient. Raji cells constitutively express 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. 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 (BCR), shown to influence BCR 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. Identifying additional CD22-targeting therapies will be important for first-line treatment of B cell malignancies as well as treatment for patients who experience relapse due to antigen escape under therapies targeting other B cell markers. 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.