The CMTM6 Knockout Raji Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population derived from the Raji B lymphocyte cell line, featuring disruption of the CMTM6 gene. This polyclonal format provides a heterogeneous loss-of-function model that preserves biological variation, allowing researchers to study CMTM6-dependent PD-L1 regulation in a physiologically relevant suspension culture system.
Raji is an Epstein-Barr virus (EBV)-positive B lymphocyte line established from a Burkitt lymphoma patient. These cells are extensively used in immunology and oncology due to their robust expression of immune checkpoint molecules, including PD-L1, and their capacity for antigen presentation and antibody secretion. Their malignant origin and viral status make them an ideal host for exploring mechanisms of immune evasion in B cell lymphomas.
CMTM6 is a transmembrane protein that stabilizes PD-L1 (CD274) on the cell surface by binding to its transmembrane domain and shielding it from STUB1 (CHIP)-mediated ubiquitination, thus preventing lysosomal degradation. Elevated PD-L1 interacts with PD-1 on T cells, recruiting SHP2 to dephosphorylate key T cell receptor signaling molecules such as ZAP70 and LCK, leading to suppression of T cell proliferation and cytotoxicity. This inhibitory axis is reinforced through crosstalk with PI3K/AKT/mTOR and NF-??B pathways. CMTM6 also cooperates with the paralog CMTM4 and participates in endosomal recycling, fine-tuning PD-L1 surface levels.
In the Raji lymphoma context, CMTM6 knockout abolishes the principal mechanism of PD-L1 stabilization, causing a marked reduction in surface PD-L1 and impairing the cells’ ability to inhibit T cell activity via PD-1 engagement. Consequently, this knockout model is a powerful tool to dissect the role of CMTM6 in B cell lymphoma immune evasion, bypassing the confounding effects of other oncogenic drivers. It is especially useful for correlating CMTM6 loss with functional T cell readouts in co-culture assays.
Researchers can employ this polyclonal knockout population for quantitative flow cytometry to monitor surface PD-L1 and CMTM6 levels, Western blotting, co-immunoprecipitation to assess protein interactions, cycloheximide chase experiments to determine PD-L1 half-life, and ubiquitination assays to confirm STUB1 involvement. Co-culture with PBMCs or Jurkat T cells permits measurement of restored T cell activation via IL-2 and IFN-?? secretion. The model is also suited for CRISPR screen validation, investigation of anti-PD-1 resistance mechanisms, and high-throughput screening of compounds that modulate PD-L1 stability. For more information or to place an order, contact Ascent Research.
