HLA-E Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human A-549 lung carcinoma cell line, featuring targeted disruption of the HLA-E gene. This polyclonal knockout model provides a heterogeneous pool of edited cells suitable for studying the loss of HLA-E function without clonal selection bias. The knockout population is generated using CRISPR/Cas9-mediated gene disruption, resulting in loss of HLA-E protein expression across the cell pool. This product serves as a versatile tool for investigating non-classical MHC class I immune checkpoint mechanisms in a lung adenocarcinoma background.
A-549 is a well-characterized human lung adenocarcinoma cell line of epithelial origin, originally derived from an alveolar basal epithelial carcinoma. These cells are KRAS-mutant and exhibit adherent epithelial morphology, making them a widely used model for non-small cell lung cancer research. A-549 cells endogenously express HLA-E and other MHC class I molecules, providing a relevant context for studying immune evasion mechanisms. Their robust expression of antigen processing and presentation machinery renders them amenable to functional assays involving NK cell and CD8+ T cell interactions. The lung adenocarcinoma background further supports investigations into tumor-immune microenvironment dynamics.
HLA-E encodes a non-classical MHC class I molecule that presents peptides to the CD94/NKG2A inhibitory receptor on NK cells and some CD8+ T cells. HLA-E preferentially binds leader peptides derived from signal sequences of classical MHC class I molecules, as well as pathogen-derived peptides such as the UL40 protein from human cytomegalovirus. The interaction between peptide-loaded HLA-E, beta-2 microglobulin, and the CD94/NKG2A heterodimer triggers intracellular signaling through SHP-1 phosphatase, leading to downstream inhibition of Vav-1-dependent actin reorganization and suppression of NK cell degranulation. Upstream regulators that transcriptionally upregulate HLA-E include interferons (IFN-gamma, IFN-alpha), tumor necrosis factor-alpha (TNF-alpha), and the NLRC5 and RFX complex. Knockout of HLA-E disrupts this inhibitory pathway, thereby relieving NK cell inhibition and promoting activation, as evidenced by enhanced CD107a degranulation and cytokine release.
In the context of A-549 lung adenocarcinoma, HLA-E plays a critical role in immune evasion by protecting tumor cells from NK cell-mediated cytotoxicity. Loss of HLA-E in this KRAS-mutant background exposes cells to heightened NK cell surveillance, modeling potential therapeutic strategies that target this immune checkpoint. The polyclonal knockout population allows assessment of heterogeneous editing outcomes and polyclonal immune responses, which better reflect the complexity of clinical scenarios. This model is particularly relevant for studying how lung cancer cells modulate innate immunity through non-classical MHC molecules, and for evaluating combinatorial therapies that include immune checkpoint inhibitors targeting the NKG2A axis.
This HLA-E knockout polyclonal cell population is suited for a broad range of functional assays. Flow cytometry can confirm loss of surface HLA-E expression, while western blotting and RT-qPCR validate gene disruption at the protein and transcript levels. Functional studies may include NK cell cytotoxicity assays (e.g., chromium release or real-time impedance-based killing), degranulation assays (CD107a mobilization), and cytokine release profiling (e.g., IFN-gamma, TNF-alpha) following co-culture with primary NK cells or NK cell lines. Additionally, these cells can be employed in tumor immunology research to dissect HLA-E-dependent immune evasion, in vaccine development to assess antigen presentation, and in transplant rejection studies to model graft-versus-host disease mechanisms. For further technical inquiries, please contact Ascent Research.
