The CD59 Knockout HAP1 Polyclonal Cells are a state-of-the-art CRISPR/Cas9-edited polyclonal cell population designed to disrupt the CD59 gene in the human HAP1 cell line. This product provides a heterogeneous pool of knockout cells, which avoids the clonal artifacts often associated with monoclonal cell lines and ensures faithful representation of gene disruption events. By eliminating CD59 protein expression, this model empowers rigorous loss-of-function studies into complement regulation and innate immunity, facilitating both mechanistic exploration and high-throughput screening applications.
HAP1 is a near-haploid cell line derived from the KBM-7 chronic myeloid leukemia (CML) line. Its haploid nature streamlines CRISPR/Cas9-mediated genome editing, as single-allele disruption reliably yields complete loss of gene function without confounding contributions from a second allele. Originating from a hematologic malignancy, HAP1 cells retain hematopoietic signaling networks and are extensively employed in functional genomics for genome-wide knockout screens, drug-sensitivity profiling, and genetic interaction mapping. This backdrop makes HAP1 an optimal host for interrogating complement pathway components and their roles in cell-autonomous immunity.
CD59 encodes a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that serves as a critical inhibitor of the complement membrane attack complex (MAC). At the molecular level, CD59 binds directly to the C8?? subunit and C9 component of the assembling MAC, blocking C9 polymerization and consequent formation of the lytic pore. This interaction protects host cells from complement-dependent cytotoxicity. CD59 expression is positively regulated by complement activation products (via alternative, classical, and lectin pathways) and pro-inflammatory cytokines, notably TNF and IL-6. The MAC assembly pathway involves sequential recruitment of complement components C5, C6, C7, C8, and multiple C9 molecules. By interfering with this terminal cascade, CD59 preserves membrane integrity and prevents autologous lysis during immune responses.
In HAP1 cells, CD59 knockout abrogates resistance to complement attack, rendering cells highly susceptible to MAC-mediated lysis. This phenotype recapitulates aspects of paroxysmal nocturnal hemoglobinuria (PNH), a disorder caused by somatic loss of CD59 on hematopoietic stem cells, leading to complement-driven hemolysis and thrombosis. The haploid HAP1 background ensures unambiguous loss-of-function, enabling precise dissection of cytotoxic mechanisms and compensatory pathways. This model facilitates the evaluation of therapeutic strategies aimed at restoring or mimicking CD59 function, including monoclonal antibodies and small-molecule complement inhibitors.
This polyclonal knockout model supports a variety of downstream applications. Researchers can employ flow cytometry-based complement killing assays, Western blotting, and RT-qPCR to verify CD59 ablation, and immunofluorescence to visualize MAC deposition on the cell surface. The cells are well-suited for high-throughput screens of complement pathway modulators and for CRISPR-based modifier screens to identify synthetic lethal interactions. Additionally, they serve as a robust platform for validating drug targets in complement-mediated conditions, such as autoimmune hemolytic anemia. For detailed product information or technical inquiries, please contact Ascent Research.
