Factor I Antibody / CFI

Overview

Factor I Antibody / CFI is a research-use-only Rabbit polyclonal (rabbit origin) Rabbit IgG directed against Factor I / CFI. It is supplied for interpretation-focused detection and comparative profiling in WB, FACS.

Key elements and design rationale

• Target context: This antibody is raised against Amino acids K19-D220 were used as the immunogen for the Factor I antibody.. Epitope context matters because isoforms, processing, and post-translational modifications can change what is accessible in a given assay.
• Format: Antigen affinity purified. Format influences background and compatibility with different detection chemistries; conjugated formats (when present) can simplify multiplexing and reduce reliance on secondary reagents.
• Species reactivity: Human, Rat. Cross-species performance can vary with sequence divergence and epitope conservation, so interpretation should be anchored with appropriate biological controls.
• Applications: WB, FACS. These indicate assay contexts where the antibody is commonly applied; actual performance depends on sample type and processing.
• Limitations: This Factor I antibody is available for research use only.. Consider these constraints when selecting controls and when comparing results across sample matrices.

Polyclonal reagents can differ in how they recognize epitope features. Monoclonal antibodies often provide more consistent epitope targeting across lots, while polyclonal preparations may broaden recognition across related epitope variants.

Biological background

Factor I / CFI refers to the gene/protein target stated in the product record. Protein targets can exhibit context-dependent expression, regulated turnover, isoform diversity, and post-translational modifications that affect apparent molecular weight and epitope accessibility. For curated functional annotation, sequence features, and expression context, consult UniProtKB P05156, NCBI Gene 3426.0, Ensembl, and Human Protein Atlas.

Research relevance and current trends

• Integrating antibody-based detection with single-cell and spatial atlasing efforts to connect RNA programs with protein-level abundance and localization in defined cell states.
• Expanding multiplexed imaging and high-content screening, where reagent specificity, cross-reactivity risk, and channel design (including direct conjugates) become central to interpretation.
• Growing emphasis on reproducibility and application-specific validation frameworks (e.g., genetic perturbation controls, orthogonal measurements, and independent antibody strategies) when drawing mechanistic conclusions.

Common research applications

• Western blot (WB): commonly used to compare relative abundance/size (e.g., band intensity or mobility shifts) between conditions.
• FACS: commonly used for qualitative/quantitative detection where compatible with the assay context.

Interpretation typically focuses on relative differences (presence/absence, fold-changes, compartment shifts, or population-level shifts) rather than absolute quantitation. When signal changes are observed, they may reflect altered expression, altered localization/trafficking, changes in modification state, or differences in sample composition; orthogonal readouts and appropriate controls help distinguish these possibilities.

Application details (record-specific): Western blot: 0.1-0.5ug/ml,FACS: 1-3ug/10^6 cells

Notes for experimental interpretation

• Product description (record-specific): Complement factor I, also known as C3b/C4b inactivator, is a protein that in humans is encoded by the CFI gene. This gene encodes a serine proteinase that is essential for regulating the complement cascade. The encoded preproprotein is cleaved to produce both heavy and light chains, which are linked by disulfide bonds to form a heterodimeric glycoprotein. This heterodimer can cleave and inactivate the complement components C4b and C3b, and it prevents the assembly of the C3 and C5 convertase enzymes. Defects in this gene cause complement factor I deficiency, an autosomal recessive disease associated with a susceptibility to pyogenic infections. Mutations in this gene have been associated with a predisposition to atypical hemolytic uremic syndrome, a disease characterized by acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. Primary glomerulonephritis with immune deposits and age-related macular degeneration are other conditions associated with mutations of this gene.
• Potential confounders: isoforms, proteolytic processing, and PTMs can change epitope presentation and apparent size; fixation/denaturation state can also expose or mask epitopes. Species differences near the epitope may affect cross-reactivity.
• Control concepts: include genetic perturbation (KO/KD) or overexpression comparisons, orthogonal measurement (e.g., transcript or proteomics), and independent antibody/epitope strategies. For conjugated reagents, include staining-only/background controls appropriate to the detection chemistry.

Immunogen/epitope context is described as: Amino acids K19-D220 were used as the immunogen for the Factor I antibody.. Monoclonal and polyclonal formats differ in epitope breadth; this can influence sensitivity to sequence variants, isoforms, or PTM-dependent recognition.

• Datasheet (FACTOR-I-ANTIBODY-CFI-R32399)

Customization & Add-ons: Can’t find the antibody you need—or require a custom format for your assay? We can help you source the best match or support custom antibody solutions for diverse research needs, including species and isotype selection, conjugations and labeling (e.g., HRP/AP, biotin, fluorophores), purification grade options (Protein A/G, affinity purified), formulation preferences (buffer selection, carrier-free, glycerol-free), custom concentrations and aliquoting, low-endotoxin options for cell-based work, and application-focused QC/validation support (project dependent). Click Talk to a Scientist to submit a request, email us at support@biohippo.com, or explore our Research Services for additional support—our team will follow up with feasibility details and next steps.