The CD47 Knockout K-562 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal cell population derived from the K-562 human leukemia cell line, featuring targeted disruption of the CD47 gene. This knockout model abolishes expression of the CD47 protein, a critical immune checkpoint ligand that mediates a “don’t eat me” signal through its receptor SIRP?? on macrophages. The polyclonal format provides a heterogeneous cell population with diverse genetic disruption profiles, enabling robust functional studies without the clonal selection biases inherent in monoclonal cell lines. The gene editing is achieved using CRISPR/Cas9 technology, resulting in loss-of-function mutations across the CD47 locus in a pool of cells, making it suitable for experiments where population-level responses are meaningful.
K-562 is a well-characterized human immortalized myelogenous leukemia cell line established from a patient with chronic myeloid leukemia in blast crisis. These cells exhibit properties of hematopoietic progenitors and serve as a model for erythroleukemia. Naturally, K-562 cells express CD47, which contributes to their ability to evade immune surveillance by inhibiting macrophage-mediated phagocytosis. The cell line is widely used in cancer biology, hematopoiesis, and drug screening due to its robust growth and responsiveness to various stimuli. The K-562 background provides a human cancer context ideal for investigating CD47??s role in immune evasion and integrin-mediated adhesion.
CD47 (integrin-associated protein) is a ligand for SIRP??, thrombospondin-1 (TSP-1), and integrins ??v??3/??IIb??3. Binding to SIRP?? on macrophages activates SHP-1 and SHP-2 phosphatases, which inhibit phagocytosis by preventing myosin-II accumulation at the synapse. CD47-TSP-1 interaction modulates adhesion, migration, and apoptosis through VEGFR2 and integrin cross-talk. Upstream regulators include transcription factors MYC, NF-??B, and HIF-1??, induced by cytokines IFN-?? and TNF-??. Downstream effects involve cytoskeletal regulators and phagocytic machinery, linking CD47 to immune checkpoint and adhesion pathways.
In the K-562 leukemia background, CD47 knockout eliminates the inhibitory signal to macrophages, rendering the cells susceptible to phagocytosis. This directly addresses the immune evasion strategy of leukemia cells, as K-562 naturally upregulates CD47 to avoid clearance. The knockout also abrogates TSP-1-mediated signaling, which can affect cell adhesion to extracellular matrix components and alter apoptosis regulation, both critical in leukemia progression. Consequently, this model enables dissection of CD47-dependent survival mechanisms and testing of therapeutic interventions aimed at blocking the CD47-SIRP?? axis. It is particularly relevant for studying chronic myeloid leukemia blast crisis, where immune escape is a hallmark of disease aggressiveness.
These polyclonal knockout cells are suitable for multiple experimental applications including immune evasion studies, phagocytosis assays, cancer immunotherapy target validation, signal transduction analyses, and drug screening. Researchers can employ flow cytometry to confirm CD47 loss, macrophage phagocytosis assays to quantitate engulfment, western blotting to assess SHP-1/SHP-2 phosphorylation status, cell adhesion assays to measure integrin function, and apoptosis assays to evaluate survival signals. The heterogeneous knockout population provides a realistic system for testing pharmacological agents targeting the CD47-SIRP?? interaction in a human leukemia model. For technical inquiries or to order this product, contact Ascent Research.
