The CSTA Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from Raji B lymphocytes, featuring targeted disruption of the cystatin A (CSTA) gene. This heterogeneous knockout model enables robust loss-of-function analyses of CSTA, an endogenous cysteine protease inhibitor, without the biases associated with clonal selection.
The Raji cell line is a Burkitt’s lymphoma-derived, Epstein-Barr virus (EBV)-positive B lymphocyte model widely used in studies of antibody production, antigen presentation, and adaptive immunity. These lymphoblastoid cells endogenously express MHC class II molecules and possess functional antigen-processing machinery, making them particularly suitable for dissecting immune regulatory pathways and B cell malignancy mechanisms.
Cystatin A functions as a selective intracellular inhibitor of cathepsins B, H, and L, cysteine proteases critically involved in invariant chain (CD74) degradation during MHC class II antigen processing. CSTA expression is transcriptionally upregulated by pro-inflammatory cytokines, including IL-1 and TNF-??, through NF-??B signaling. By binding and inhibiting these cathepsins, CSTA directly modulates proteolytic processing within the endocytic pathway, serving as a molecular link between cytokine signals, protease activity, and antigen presentation.
In Raji B cells, disruption of CSTA removes endogenous restraint on cathepsin activity, leading to dysregulated invariant chain processing and altered MHC class II-peptide loading. This perturbation can profoundly impact antigen presentation to CD4+ T cells and may contribute to immune evasion strategies exploited by lymphoma cells. Given the association of CSTA with psoriasis, cancer invasion, and lymphoma, this knockout model provides a powerful tool to investigate cathepsin-dependent immune modulation in B cell lymphomas and to explore mechanisms underlying tumor immune escape.
Researchers can employ these polyclonal knockout cells in a variety of functional assays. Flow cytometry allows quantification of cell surface MHC class II expression, while cathepsin activity assays and co-immunoprecipitation with cathepsin B, H, or L reveal direct biochemical interactions. Western blotting for invariant chain processing and cytokine secretion profiling (ELISA) uncover downstream effects, and T cell activation assays assess functional antigen presentation capacity. These approaches are integral to antigen presentation research, cysteine protease biology, and lymphoma pathogenesis studies. For further information and support, please contact Ascent Research.
