Cleaved-C1R (I464) Antibody

What is Cleaved-C1R (I464) Antibody and what does it detect?

Cleaved-C1R (I464) Antibody is a rabbit polyclonal antibody that specifically recognizes the fragment of activated C1r light chain (LC) protein resulting from cleavage adjacent to isoleucine 464 (I464). This antibody detects endogenous levels of the activated form of C1r LC, which has a molecular weight of approximately 27kDa . The antibody is produced using synthetic peptides derived from the human C1R protein spanning amino acids 445-494 . It plays a crucial role in investigating the classical pathway of the complement system activation.

What applications is Cleaved-C1R (I464) Antibody validated for?

The antibody has been primarily validated for Western Blotting (WB) and Enzyme-Linked Immunosorbent Assay (ELISA) applications . The recommended dilution ranges are:

Optimal dilutions should be determined by each laboratory for their specific experimental conditions . The antibody has not been extensively tested in other applications such as immunohistochemistry or immunofluorescence as indicated by multiple manufacturers .

What species reactivity has been confirmed for this antibody?

The antibody shows confirmed reactivity with human samples across all manufacturers . Some versions of the antibody have also been reported to cross-react with rat and mouse samples , though this may vary between suppliers. Researchers working with non-human models should perform validation experiments to confirm cross-reactivity with their specific samples.

What is the optimal sample preparation protocol for detecting cleaved C1r using this antibody in Western blot applications?

For optimal detection in Western blot applications:

• Prepare tissue or cell lysates using a standard lysis buffer containing protease inhibitors to prevent further degradation of the complement proteins.

• Quantify protein concentration and load 20-50 μg of total protein per lane.

• Separate proteins using SDS-PAGE (10-12% gel recommended for optimal resolution of the 27kDa target band).

• Transfer proteins to a PVDF or nitrocellulose membrane.

• Block with 5% non-fat milk or BSA in TBST for 1 hour at room temperature.

• Incubate with primary antibody diluted 1:500-1:2000 in blocking buffer overnight at 4°C .

• Wash thoroughly with TBST.

• Incubate with appropriate HRP-conjugated secondary antibody.

• Develop using ECL detection system.

Include positive controls such as serum samples or cell lines known to express activated C1r to validate specificity .

How should the antibody be stored to maintain optimal activity?

The antibody is typically supplied in liquid form in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide . For optimal storage:

• Upon receipt, aliquot the antibody to minimize freeze/thaw cycles.

• Store at -20°C for up to 1 year from the date of receipt .

• Avoid temperatures below -25°C as this may affect antibody stability .

• Thaw aliquots on ice before use and return to storage immediately after use.

• Do not expose to repeated freeze/thaw cycles as this can degrade antibody performance .

How can Cleaved-C1R (I464) Antibody be used to study complement activation in disease models?

The antibody provides a valuable tool for investigating classical complement pathway activation in various disease models:

• Autoimmune disease research: Monitor C1r activation in systemic lupus erythematosus (SLE) models, where complement deficiencies are known to increase disease susceptibility .

• Infection models: Assess classical pathway activation during microbial challenges, as C1r deficiency increases susceptibility to infections .

• Tissue-specific complement activation: Investigate complement involvement in adipose tissue, colon endothelium, liver, plasma, and skin, where C1r shows tissue specificity .

• Time-course experiments: Design experiments to track C1r cleavage over time following inflammatory stimuli to understand activation kinetics.

• Treatment efficacy assessment: Use the antibody to evaluate the impact of therapeutic interventions on complement activation in preclinical models.

For these applications, researchers should design appropriate control experiments including C1r-deficient samples when available .

What are the known limitations of using this antibody for complement system research?

Researchers should be aware of several important limitations:

• Epitope specificity: The antibody recognizes only the cleaved form at I464, so it cannot detect uncleaved C1r or alternative cleavage products .

• Sample handling: Complement proteins are susceptible to spontaneous activation during sample handling, potentially leading to false-positive results. Samples should be processed rapidly at 4°C with appropriate inhibitors .

• Cross-reactivity variations: While advertised for human, rat, and mouse in some cases, cross-reactivity efficiency may vary. Validation in each experimental system is strongly recommended .

• Limited application validation: The antibody has primarily been validated for WB and ELISA, with limited data available for other applications like immunohistochemistry or immunoprecipitation .

• Quantification challenges: Western blot results are semi-quantitative; researchers requiring absolute quantification should consider supplementing with additional techniques such as mass spectrometry .

What are common issues encountered with Western blot detection using this antibody and how can they be resolved?

For persistent issues, a comparison between different tissue samples with known C1r expression levels may help establish optimal working conditions .

How can the specificity of the Cleaved-C1R (I464) Antibody be validated in experimental settings?

To validate antibody specificity:

• Positive controls: Include samples known to contain cleaved C1r, such as serum activated with immune complexes.

• Negative controls: Use C1r-knockout samples or tissues from C1r-deficient patients if available.

• Peptide competition assay: Pre-incubate the antibody with excess immunizing peptide (aa 445-494) to block specific binding sites, which should eliminate specific signal.

• Size verification: Confirm that the detected band appears at approximately 27kDa, the expected molecular weight of the cleaved C1r light chain .

• Correlation with functional assays: Compare antibody detection results with functional complement activation assays such as hemolytic assays or C4 deposition ELISA.

How does detection of cleaved C1r compare with other markers of classical complement pathway activation?

The detection of cleaved C1r represents an early and specific marker of classical pathway activation:

Researchers investigating complement activation should consider combining detection of cleaved C1r with downstream markers for comprehensive pathway analysis .

What complementary methodologies can be combined with Cleaved-C1R (I464) Antibody analysis for comprehensive complement system research?

For comprehensive complement system research, consider integrating:

This multi-method approach provides a more comprehensive understanding of complement activation status than any single technique alone.

How is Cleaved-C1R (I464) Antibody utilized in studying the role of complement in autoimmune diseases?

The antibody serves as an important tool in autoimmune disease research:

• Systemic Lupus Erythematosus (SLE): C1r deficiency has been associated with increased SLE susceptibility. Researchers can use this antibody to assess classical pathway activation in patient samples or animal models, correlating C1r cleavage with disease severity and autoantibody production .

• Rheumatoid Arthritis: The antibody can help evaluate classical complement activation in synovial fluid and tissue, potentially distinguishing between local and systemic complement activation.

• Complement Deficiency Analysis: In patients with suspected complement deficiencies, the antibody can help determine if the defect occurs at or before C1r activation, or downstream of this point .

• Treatment Response Monitoring: By assessing changes in C1r cleavage before and after immunosuppressive therapy, researchers can gain insights into treatment mechanisms and efficacy.

• Tissue-Specific Activation Patterns: The antibody allows for investigation of tissue-specific complement activation patterns in autoimmune conditions affecting different organs .

What considerations should be made when using this antibody to investigate the complement system in neurodegenerative disorders?

When investigating neurodegenerative disorders:

• Blood-Brain Barrier Considerations: Assess whether peripheral complement activation (detected in serum) correlates with central nervous system pathology.

• Tissue Preparation: Brain tissue requires special fixation and processing protocols to preserve complement proteins while maintaining antigen accessibility.

• Cell-Type Specific Activation: Consider combining with cell-type specific markers to determine which neural cells (neurons, microglia, astrocytes) are associated with complement activation.

• Background Issues: Aged brain tissue often has high autofluorescence - optimize detection methods accordingly if performing immunofluorescence.

• Temporal Dynamics: Design experiments to capture both acute and chronic complement activation, as neurodegenerative diseases typically progress over extended periods.

• Control Selection: Age-matched controls are essential, as baseline complement activation may increase with normal aging independently of disease processes.

This antibody could potentially help elucidate the role of classical complement pathway activation in conditions such as Alzheimer's disease, where complement proteins have been identified in association with amyloid plaques and neurofibrillary tangles.