The KLRB1 Knockout A-549 Polyclonal Cells product consists of a CRISPR/Cas9-edited polyclonal knockout cell population derived from the A-549 cell line, designed for targeted disruption of the KLRB1 gene. This polyclonal knockout model enables the study of loss-of-function effects on CD161 receptor expression and downstream signaling in a lung adenocarcinoma background, without selection for clonal homogeneity or predefined mutation profiles. The use of polyclonal knockout cells reflects the endogenous diversity of editing outcomes, providing a robust system for functional genomics and cell-based assays relevant to cancer immunology and immune checkpoint research.
A-549 cells are a widely used human epithelial cell line originally isolated from the lung adenocarcinoma of a 58-year-old Caucasian male. These adherent cells maintain characteristic features of alveolar type II pneumocytes and serve as a standard model for investigating lung adenocarcinoma biology, drug response, and tumor microenvironment interactions. The A-549 background supports studies on cell proliferation, migration, and invasion, as well as interactions with immune cells such as natural killer (NK) cells and T lymphocytes. Their stable growth characteristics and well-documented genome make them suitable for CRISPR/Cas9-mediated gene disruption and subsequent functional assays.
The KLRB1 gene encodes CD161, an inhibitory C-type lectin receptor expressed predominantly on NK cells and subsets of T cells. CD161 binds its ligand CLEC2D (LLT1) to regulate cellular cytotoxicity and cytokine production through recruitment of SHP-1 and SHP-2 phosphatases, which attenuate ITAM-based activation signals mediated by adaptors like DAP12. Upstream, CD161 expression is controlled by cytokines such as IL-2 and IL-15, as well as transcription factors T-bet and Eomes. Downstream signaling typically leads to reduced secretion of IFN-?? and TNF-??, while key pathway components include CLEC2D, SHP-1, DAP12, ZAP70, and NF-??B. Disruption of KLRB1 in A-549 cells eliminates CD161 surface expression, potentially altering the inhibitory input that modulates these signaling cascades and shifting the balance of cytokine responses and immune cell recognition.
In the context of lung adenocarcinoma, the CD161/LLT1 axis has been implicated in immune evasion, where aberrant expression of LLT1 on tumor cells can engage CD161 on infiltrating immune cells to suppress antitumor immunity. By knocking out KLRB1 in A-549 cells, this model enables dissection of CD161-dependent interactions between tumor cells and effector lymphocytes. Researchers can investigate how loss of CD161 alters A-549 cell susceptibility to NK cell-mediated cytotoxicity, T cell activation, and cytokine production profiles. This system provides a platform to explore the functional consequences of CD161 deficiency in a tumor cell background that expresses the cognate ligand LLT1, thereby facilitating mechanistic studies of immunoregulatory signaling within the tumor microenvironment.
Typical applications include immune checkpoint research, co-culture cytotoxicity assays with NK cells or T cells, and screening of CD161-targeted immunotherapies. The knockout cells are compatible with a range of techniques such as flow cytometry for CD161 validation, RT-qPCR for transcriptional analysis, Western blotting for protein expression, ELISA for IFN-?? and granzyme B secretion, and phospho-protein analysis for downstream signaling events. Migration and invasion assays can assess phenotypic changes, while immunofluorescence allows visualization of receptor localization. These applications support lung cancer progression modeling and the evaluation of therapeutic strategies that disrupt the CD161/LLT1 inhibitory axis. For further details or custom inquiries, contact Ascent Research.
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