The CD59 Knockout A2780 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal population derived from the A2780 human ovarian adenocarcinoma line, in which the CD59 gene has been disrupted to ablate its encoded complement regulatory protein. This polyclonal knockout product eliminates CD59-mediated inhibition of the membrane attack complex (MAC), rendering the cells susceptible to complement-dependent cytotoxicity (CDC). The population is generated by non-homologous end joining following Cas9-mediated double-strand breaks, resulting in a heterogeneous distribution of loss-of-function alleles without clonal selection. The product is designed for researchers investigating complement evasion mechanisms, therapeutic antibody-mediated CDC, and CD59-dependent signaling pathways in an ovarian cancer context.
The A2780 cell line was originally established from an untreated patient with ovarian endometrioid adenocarcinoma and has become a widely employed model in epithelial ovarian cancer research. These adherent cells exhibit typical epithelial morphology and retain key oncogenic alterations relevant to high-grade serous and endometrioid histotypes. Their well-characterized growth properties and responsiveness to chemotherapeutic agents make A2780 a robust platform for functional genomics studies. The introduction of a CD59 knockout in this background provides a physiologically relevant system to explore how ovarian cancer cells modulate complement attack, particularly in the peritoneal tumor microenvironment where complement proteins are abundant.
CD59 is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that functions as a critical negative regulator of the terminal complement cascade. It binds to the C8 alpha chain and C9 within the assembling MAC, sterically blocking C9 polymerization and pore formation, thereby protecting host cells from autologous complement-mediated lysis. CD59 expression is modulated by upstream regulators including transforming growth factor-beta (TGF-??) and inflammatory cytokines, linking its levels to the broader immune context. Beyond complement, CD59 interacts with CD2 to co-stimulate T cell activation, indicating a dual role in innate and adaptive immunity. Downstream targets include C8, C9, MAC (C5b-9) assembly, and cell survival signaling pathways that are engaged upon sublytic MAC deposition. In the knockout cells, the absence of CD59 permits unopposed C5b-8 and C5b-9 complex formation, leading to rapid C9 polymerization and MAC insertion when cells encounter complement proteins.
In the A2780 ovarian cancer model, CD59 contributes to immune evasion by shielding tumor cells from complement-mediated surveillance. Loss of CD59 function therefore unmasks these cells to CDC, recapitulating a therapeutically desirable vulnerability that can be exploited by tumor-targeting antibodies such as those directed against HER2, EGFR, or EpCAM. The knockout model also enables dissection of CD59 signaling functions that extend beyond complement inhibition, including its interplay with receptor tyrosine kinases and pro-survival cascades activated by sublytic MAC. Furthermore, it serves as a relevant tool for modeling complement susceptibility patterns observed in cancers with acquired CD59 deficiency, providing insights into the mechanisms underlying resistance to antibody-based immunotherapies.
Research applications span complement evasion studies, high-throughput screening of therapeutic antibodies that enhance CDC, and investigation of CD59-mediated signaling beyond complement inhibition. Typical assays include flow cytometric verification of CD59 surface loss, CDC assays using human serum or purified complement components, immunofluorescence detection of MAC (C5b-9) deposition, and cell viability readouts following complement challenge. Western blotting for C9 polymerization can further validate functional knockout at the biochemical level. The polyclonal nature of the population allows rapid assessment of gene disruption effects without the need for clonal expansion, facilitating dose?Cresponse studies and antibody screening campaigns. For detailed technical specifications or ordering information, please contact Ascent Research.
