The CD55 Knockout Huh-7 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human hepatocellular carcinoma cell line Huh-7, with targeted disruption of the CD55 gene. CD55 encodes decay-accelerating factor (DAF), a glycosylphosphatidylinositol (GPI)-anchored membrane protein that serves as a crucial negative regulator of the complement cascade. This knockout model provides a powerful tool for dissecting complement-mediated immune evasion mechanisms, particularly in the context of hepatic cancer biology. The polyclonal nature of this product reflects a heterogeneous population of edited cells, enabling researchers to study loss-of-function effects without clonal selection artifacts, and it is suitable for a broad range of functional and comparative assays in immunology and oncology.
Huh-7 is an extensively characterized human hepatocellular carcinoma cell line that displays adherent epithelial morphology and retains many differentiated hepatic functions, including the expression of liver-specific metabolic enzymes and acute-phase proteins. This cell line is widely employed as a model system for investigating liver cancer pathogenesis, hepatotropic virus infections, drug metabolism, and hepatocyte biology. Its tumorigenic origin and well-documented genetic profile make it particularly valuable for studying oncogenic signaling and tumor?Cimmune interactions. The availability of a CD55 knockout in this genetic background facilitates detailed examination of complement regulatory networks in a liver-relevant cellular context, linking innate immunity with hepatocarcinogenesis.
At the molecular level, CD55 functions by accelerating the dissociation of C3 and C5 convertases??key enzymatic complexes of the complement system??thereby preventing the amplification of complement activation and the formation of the cytolytic membrane attack complex (C5b-9). This protein directly interacts with complement components C3b and C4b, as well as with the adhesion G protein-coupled receptor CD97, factor B, and complement receptors, positioning it at the intersection of complement regulation and immune cell adhesion. CD55 expression is modulated by upstream signals including the pro-inflammatory cytokines TNF-alpha and IL-1, the transcription factor NF-??B, and hypoxia, all of which are commonly activated in the tumor microenvironment. Downstream consequences of CD55 activity include reduced C3b opsonization, suppressed C5b-9 assembly, inhibition of complement-mediated lysis, and modulation of T cell activation, highlighting its multifaceted role in immune homeostasis.
In the Huh-7 hepatocellular carcinoma context, CD55 knockout abrogates this intrinsic protective mechanism, rendering the cells highly susceptible to complement-dependent cytotoxicity??a phenomenon of significant therapeutic interest given the liver??s constant exposure to complement proteins from the portal circulation. By removing a key immune evasion tactic, this model enables the investigation of how liver cancer cells might be targeted by complement-activating monoclonal antibodies or nanoparticle-based drug delivery systems. Moreover, it provides a platform to explore the interplay between complement inhibition and other oncogenic pathways, such as those driven by NF-??B and hypoxia, which are frequently dysregulated in hepatocellular carcinoma and can further alter CD55 expression levels.
Typical research applications of this polyclonal knockout product include complement-dependent cytotoxicity assays to assess the efficacy of therapeutic antibodies, flow cytometric analysis of complement regulatory protein profiles, western blotting for downstream signaling components, immunofluorescence localization of membrane attack complex deposition, and viral entry studies using echovirus or coxsackievirus that exploit CD55 as a cellular receptor. These cells are also valuable for modeling paroxysmal nocturnal hemoglobinuria-like complement hypersensitivity in a hepatic environment, evaluating the contribution of CD55 to tumor immune evasion, and screening for compounds that restore or replace complement regulatory function. For additional technical information and ordering details, please contact Ascent Research.
