The LGMN Knockout Raji Polyclonal Cells comprise a heterogeneous population of Raji B lymphocytes genetically modified via CRISPR/Cas9-mediated disruption of the LGMN gene, which encodes the lysosomal cysteine protease legumain. Delivered as a polyclonal knockout cell pool, this model provides a physiologically relevant system to investigate loss-of-function effects without clonal selection, preserving genomic diversity that may influence endolysosomal function and antigen presentation pathways. The product is designed for researchers requiring a robust, non-monoclonal knockout background for comparative biochemical, immunological, and cell-based assays in a human B-cell lineage context.
Derived from an Epstein-Barr virus-positive Burkitt lymphoma patient, the Raji cell line is a widely characterized B-lymphocyte model exhibiting rapid proliferation and retained features of germinal center B cells, including surface immunoglobulin expression and the capacity for internalizing and processing exogenous antigens. Its EBV-driven immortalization maintains active endocytic trafficking and constitutive MHC class II expression, making it particularly advantageous for dissecting antigen processing machinery. These cells express essential components of the lysosomal proteolytic network, and their lymphoma origin renders them a relevant host for studying protease contributions to malignant phenotypes and immune evasion.
Legumain (asparaginyl endopeptidase) functions predominantly in late endosomes and lysosomes, where it cleaves protein substrates after asparagine residues to activate other hydrolases and process antigens for loading onto MHC class II molecules. Its activity is transcriptionally regulated by TFEB and STAT3 downstream of Notch signaling, and it operates in coordination with cathepsin L and the invariant chain (CD74) to facilitate durable peptide?CMHC class II complexes. Legumain also interacts with cystatins, which modulate its proteolytic activity, and cross-talks with cathepsins and integrin ??v??3 to influence extracellular matrix remodeling through downstream targets such as MMP2, fibronectin, and collagen.
Ablation of legumain in Raji B cells is predicted to impair the cleavage of invariant chain intermediates and the generation of specific antigenic peptides, thereby reducing surface presentation of MHC class II?Cbound epitopes. This interferes with CD4+ T-cell recognition, alters endolysosomal degradation dynamics, and may disturb feedback loops involving STAT3 and TFEB. Because Raji cells originate from Burkitt lymphoma, legumain knockout also serves as a platform to study how protease-dependent antigen processing intersects with B-cell lymphoma biology, tumor microenvironment communication, and matrix remodeling mediated by MMP2 and integrin pathways.
Applications include detailed antigen processing studies employing MHC class II presentation assays and fluorogenic substrate activity measurements to quantify residual protease function. Western blotting for legumain confirms knockout efficiency, while flow cytometry can monitor changes in surface markers linked to immune synapse formation. Migration and invasion assays further enable exploration of tumor?Cstroma interactions modulated by legumain-dependent matrix cleavage. This polyclonal knockout population is suitable for high-content screens, co-culture experiments, and mechanistic dissection of endolysosomal proteolysis in B-cell malignancies. For additional information, please contact Ascent Research.
