SPBC1773.17c Antibody

What is IL-17C and how does it differ from other IL-17 family members?

IL-17C is a unique member of the Interleukin-17 family, which comprises six proteins (IL-17, IL-17B through IL-17F) that share a conserved cysteine-knot fold near the C-terminus but diverge considerably at the N-terminus . Unlike other family members, IL-17C is specifically produced by keratinocytes rather than immune cells and plays a distinct role in epithelial inflammation through "feed-forward" mechanisms that amplify inflammatory responses .

Human IL-17C is encoded by a cDNA sequence that produces a 197 amino acid residue protein with an 18 amino acid signal peptide . While it shares only 15-30% amino acid sequence identity with other IL-17 family members, human and mouse IL-17C share 83% sequence identity, suggesting evolutionary conservation of function . Unlike IL-17B (which exists as a non-covalently linked dimer), IL-17C forms disulfide-linked dimers similar to other family members .

What are the primary applications for IL-17C antibodies in research?

IL-17C antibodies can be used in various research applications including:

• Immunohistochemistry (IHC) - For detection of IL-17C in tissue sections, particularly in inflammatory conditions. The antibody has been validated for detection in paraffin-embedded sections of human Crohn's intestine, with specific staining localized to the cytoplasm of lymphocytes .

• Flow cytometry - For intracellular staining in cell lines, such as PC-3 human prostate cancer cells, requiring fixation with paraformaldehyde and permeabilization with saponin .

• ELISA - For sandwich immunoassays to quantify IL-17C in experimental samples .

• Mechanistic studies - To neutralize IL-17C function in research models of inflammatory skin conditions .

What is the expression pattern of IL-17C in healthy and diseased tissues?

IL-17C demonstrates a highly restricted expression pattern in normal tissues. It has been detected as a rare expressed sequence tag (EST) in adult prostate and fetal kidney libraries . In pathological conditions, IL-17C expression is significantly upregulated in inflammatory skin diseases, particularly in keratinocytes of patients with atopic dermatitis and psoriasis .

The cytokine's expression is induced as part of inflammatory feedback loops, where it serves to amplify inflammatory responses through various signaling mechanisms . Detection methods using IL-17C antibodies have revealed its presence in the cytoplasm of lymphocytes in intestinal tissues from Crohn's disease patients and intracellularly in cancer cell lines like PC-3 .

How should researchers design IL-17C neutralization experiments in inflammatory skin disease models?

When designing IL-17C neutralization experiments, researchers should consider:

• Model selection: Different animal models may represent different aspects of inflammatory skin diseases. For example, models that recapitulate T helper type 2 (Th2) cell responses are more relevant for atopic dermatitis, while those that involve Th17/Th22 pathways may better represent psoriasis .

• Antibody specifications: Use validated neutralizing antibodies with confirmed specificity for IL-17C. The clone #177114 (MAB1234) has been used successfully in various applications .

• Dosing regimens: Consider both administration route (intravenous vs. subcutaneous) and dosing intervals. Clinical studies have explored doses ranging from 1-10 mg/kg intravenously every 2-4 weeks, or 320 mg subcutaneously every 2 weeks .

• Readout parameters: Measure multiple endpoints including clinical scores, histological features, molecular markers (especially S100A proteins), and cytokine profiles to thoroughly assess therapeutic effects .

• Control groups: Include appropriate controls such as isotype antibodies and positive control treatments with established efficacy in your model system .

What methodological considerations are important when using IL-17C antibodies for immunohistochemistry?

For optimal immunohistochemical detection of IL-17C in tissue sections, researchers should consider:

How can researchers distinguish between IL-17C effects and those of other IL-17 family members in experimental models?

Differentiating IL-17C-specific effects from those of other IL-17 family members requires:

• Specific antibodies: Use highly specific monoclonal antibodies with minimal cross-reactivity to other IL-17 family members. Validate specificity through appropriate controls and blocking studies .

• Comparative studies: Design experiments that compare neutralization of different IL-17 family members side-by-side in the same model system .

• Genetic approaches: Consider using knockout or knockdown models specific for IL-17C or its receptor to complement antibody studies .

• Receptor analysis: IL-17C signals through different receptors than other family members. IL-17RA and IL-17RE form the receptor complex for IL-17C, while IL-17A and IL-17F signal through IL-17RA and IL-17RC heterodimers .

• Downstream biomarkers: Identify and measure IL-17C-specific downstream targets. IL-17C specifically induces certain S100A proteins and antimicrobial peptides in keratinocytes that may have different expression patterns compared to IL-17A/F-induced genes .

• Cell source analysis: Remember that IL-17C is primarily produced by epithelial cells (keratinocytes), whereas IL-17A and IL-17F are predominantly produced by T cells and innate lymphoid cells .

What are the optimal storage and handling conditions for IL-17C antibodies?

For maximum stability and functionality of IL-17C antibodies:

• Storage temperature: Store at -20 to -70°C for long-term storage (up to 12 months from receipt) .

• Short-term storage: When reconstituted, store at 2 to 8°C under sterile conditions for up to 1 month .

• Intermediate storage: Reconstituted antibody can be stored at -20 to -70°C under sterile conditions for up to 6 months .

• Freeze-thaw cycles: Use a manual defrost freezer and avoid repeated freeze-thaw cycles that can damage antibody structure and function .

• Reconstitution: For lyophilized antibodies, reconstitute carefully following manufacturer's instructions to maintain proper concentration and sterility .

• Working solutions: Prepare fresh dilutions for each experimental run whenever possible to ensure consistent performance .

How should researchers address potential discrepancies between in vitro and in vivo findings with IL-17C antibodies?

When encountering discrepancies between in vitro and in vivo results:

• Biological complexity: Recognize that IL-17C functions within complex inflammatory circuits in vivo that may not be fully replicated in simplified in vitro systems . In vivo, IL-17C participates in feed-forward mechanisms involving multiple cell types and mediators .

• Antibody penetration: Consider whether the antibody effectively reaches target tissues in vivo. Different administration routes (intravenous vs. subcutaneous) yield different pharmacokinetic profiles, with subcutaneous administration showing approximately 55% bioavailability compared to intravenous dosing .

• Dose optimization: Determine whether suboptimal dosing might explain discrepant results. Clinical studies suggest that steady-state drug levels are reached at 2-4 weeks , so experimental timeframes should account for this.

• Model selection: Evaluate whether your animal model accurately recapitulates the human disease features relevant to IL-17C biology. Different models may emphasize different aspects of disease pathophysiology .

• Endpoint selection: Ensure that the endpoints measured in vitro correspond appropriately to those assessed in vivo. For example, the ability of IL-17C to stimulate TNF-alpha and IL-1 beta release from monocytic cell lines in vitro may not directly translate to clinical improvement metrics used in vivo.

What controls should be included when validating new batches of IL-17C antibodies?

Thorough validation of new antibody batches should include:

• Isotype controls: Use appropriate isotype-matched control antibodies (e.g., MAB003 for mouse monoclonal antibodies) to assess non-specific binding .

• Known positive samples: Test the new batch on samples with confirmed IL-17C expression, such as:

  • Paraffin-embedded sections of human Crohn's intestine

  • Permeabilized PC-3 human prostate cancer cells

  • Stimulated keratinocytes from inflammatory skin disease models

• Western blot verification: If applicable, confirm specificity by western blot against recombinant IL-17C protein and tissue/cell lysates.

• Dilution series: Perform titration experiments to confirm optimal working concentration for each application.

• Cross-reactivity testing: Verify lack of cross-reactivity with other IL-17 family members, particularly those with higher sequence homology.

• Functional validation: For neutralizing antibodies, confirm that the new batch effectively blocks IL-17C-induced functional responses (e.g., cytokine production or gene expression changes).

• Inter-batch comparison: Run side-by-side comparisons with previously validated batches to ensure consistent performance.

What lessons can be learned from clinical trials of anti-IL-17C antibody therapeutics?

The clinical development of anti-IL-17C antibodies has yielded several important insights:

• Safety profile: Anti-IL-17C monoclonal antibodies like MOR106 demonstrated favorable safety and tolerability in Phase 1 and 2 clinical trials, with a profile consistent with other monoclonal antibodies approved for atopic dermatitis .

• Pharmacokinetics: Subcutaneous administration of anti-IL-17C antibodies showed approximately 55% bioavailability compared to intravenous administration, with steady-state levels reached after 2-4 weeks of treatment .

• Dosing considerations: Clinical studies explored various dosing regimens, including intravenous administration every 2 or 4 weeks (1-10 mg/kg) and subcutaneous dosing every 2 weeks (320 mg) .

• Efficacy limitations: Despite compelling preclinical data suggesting IL-17C's role in inflammatory skin conditions, clinical trials of MOR106 for atopic dermatitis were terminated after futility analysis indicated a low probability of achieving primary efficacy endpoints .

• Target validation: The disconnect between preclinical findings and clinical outcomes highlights the complexity of inflammatory pathways in human disease and the potential limitations of current animal models in predicting clinical efficacy .

• Indication selection: While ineffective for atopic dermatitis, the favorable safety and pharmacokinetic characteristics of anti-IL-17C antibodies warrant investigation in other indications where IL-17C may play a more central pathogenic role .

How does IL-17C signaling interact with other inflammatory pathways in epithelial tissues?

IL-17C functions within complex inflammatory networks:

• Synergistic amplification: IL-17C participates in synergistic "feed-forward" mechanisms in the epidermis that amplify inflammatory responses through interactions with cellular immune components .

• Dual pathway modulation: IL-17C appears capable of modulating both Th2-dominant and Th17/Th22-dominant inflammatory circuits that drive different features of atopic dermatitis and psoriasis, respectively .

• Keratinocyte activation: As a keratinocyte-derived cytokine, IL-17C acts in autocrine and paracrine fashions to induce S100A proteins and other molecules associated with epidermal hyperplasia .

• Cytokine induction: IL-17C stimulates the release of pro-inflammatory mediators like TNF-alpha and IL-1 beta from monocytic cells, similar to IL-17B .

• Tissue-specific responses: IL-17C's restricted expression pattern suggests tissue-specific functions, with current evidence pointing to particularly important roles in epithelial tissues like skin and intestinal mucosa .

• Receptor specificity: IL-17C signals through a distinct receptor complex (IL-17RA/IL-17RE) compared to other IL-17 family members, allowing for targeted therapeutic interventions .

What novel applications of IL-17C antibodies are emerging in fields beyond dermatology?

While IL-17C biology has been most extensively studied in skin inflammation, emerging evidence suggests potential applications in:

• Gastrointestinal inflammation: IL-17C expression in intestinal tissues from Crohn's disease patients suggests potential roles in inflammatory bowel diseases. Detection methods using IL-17C antibodies have revealed its presence in the cytoplasm of intestinal lymphocytes .

• Cancer immunology: The detection of IL-17C in cell lines like PC-3 (prostate cancer) suggests possible roles in tumor microenvironment regulation . IL-17 family cytokines have complex roles in cancer, sometimes promoting and sometimes inhibiting tumor growth depending on context.

• Mucosal immunity: Given IL-17C's expression in epithelial tissues, investigating its function at mucosal barriers beyond the skin could reveal important roles in host defense against pathogens.

• Antimicrobial responses: IL-17C induces antimicrobial peptides in epithelial cells, suggesting potential applications in studying host defense mechanisms against bacterial and fungal infections.

• Autoimmunity research: The involvement of IL-17C in inflammatory amplification circuits suggests it may play roles in autoimmune conditions affecting epithelial tissues beyond currently studied diseases.

What methodological improvements could enhance IL-17C detection sensitivity and specificity?

Advancing IL-17C research requires improved detection methods:

• Multiplex approaches: Developing methods to simultaneously detect multiple IL-17 family members in the same sample would allow better understanding of their coordinated functions.

• In situ detection: Refining techniques for visualizing IL-17C production and signaling in intact tissues could provide spatial context for understanding its functions in complex microenvironments.

• Single-cell analysis: Adapting IL-17C antibodies for single-cell techniques like mass cytometry or imaging mass cytometry would enable more precise identification of producing and responding cell populations.

• Reporter systems: Creating improved reporter cell lines or transgenic reporter animals for IL-17C expression and signaling would facilitate real-time monitoring of pathway activation.

• High-sensitivity ELISAs: Developing more sensitive detection assays would allow quantification of IL-17C in biological samples where it may be present at very low concentrations.

• Cross-species reactivity: Generating antibodies with confirmed reactivity across multiple species would facilitate translation between model systems.