IL17B Human, Sf9

What is IL17B and how does it relate to the broader IL-17 family?

IL17B (also known as Interleukin-17B, IL-17B, Cytokine Zcyto7, Interleukin-20, Neuronal interleukin-17-related factor, IL20, NIRF, or ZCYTO7) is a member of the IL-17 cytokine family . The IL-17 family comprises at least six pro-inflammatory cytokines that share a conserved cysteine-knot structure but diverge at the N-terminus . IL17B is most homologous with IL17D, while IL-17 and IL-17F form a distinct subgroup sharing 44% amino acid homology, compared to the more limited 15-27% homology seen with other family members like IL17B .

What are the structural characteristics of recombinant human IL17B expressed in Sf9 cells?

Recombinant human IL17B produced in Sf9 baculovirus cells is a single, glycosylated polypeptide chain containing 169 amino acids (positions 21-180 of the native sequence) with a molecular mass of 19.2kDa . When analyzed by SDS-PAGE, it typically appears as an 18-28kDa band due to glycosylation effects. The recombinant protein is expressed with a 6-amino acid His-tag at the C-terminus and is purified using proprietary chromatographic techniques . Like other IL-17 family members, IL17B is secreted as a dimer, which is crucial for its biological function .

How should researchers properly store and handle IL17B preparations?

IL17B protein solution (0.25mg/ml) is typically supplied in phosphate-buffered saline (pH 7.4) containing 10% glycerol . For optimal stability, the protein should be stored at 4°C if the entire vial will be used within a short period . For long-term storage, it is advisable to aliquot the protein to avoid repeated freeze-thaw cycles that could compromise structural integrity and biological activity. Sterile handling procedures should be maintained to prevent contamination that could interfere with experimental results.

What receptors does IL17B interact with and how does this differ from other IL-17 family members?

IL17B specifically binds to the IL17B receptor but does not interact with the IL17 receptor that binds IL17A . This receptor specificity is crucial for understanding the biological activities and cellular targets of IL17B. Recent research has shown that IL17B and IL17C do not appear to be ligands for the conventional IL17 receptor, suggesting the existence of other molecules that serve as cognate receptors for these factors . This distinct receptor binding profile differentiates IL17B's signaling pathways from those of other IL-17 family cytokines.

How do post-translational modifications in Sf9-expressed IL17B compare to mammalian cell-expressed IL17B?

Sf9 insect cells perform many post-translational modifications similar to mammalian cells, but with notable differences in glycosylation patterns. IL17B Human produced in Sf9 cells undergoes glycosylation, resulting in a molecular weight range of 18-28kDa when visualized by SDS-PAGE, compared to the calculated 19.2kDa of the unmodified polypeptide . Researchers should be aware that these differences in glycosylation may influence protein stability, receptor binding affinity, and biological activity compared to native human IL17B or variants expressed in mammalian cells. Comparative studies of IL17B from different expression systems may be necessary when precise glycosylation patterns are critical to experimental outcomes.

What are the complexities in designing neutralizing antibodies against IL17B for therapeutic applications?

Developing effective neutralizing antibodies against IL17B presents several challenges due to its structural similarities with other IL-17 family members. Researchers must consider:

• Epitope specificity: Antibodies must target regions unique to IL17B to avoid cross-reactivity with other IL-17 family cytokines, particularly IL17D with which it shares highest homology .

• Receptor binding interface: Effective neutralizing antibodies should block the interaction between IL17B and its receptor without affecting beneficial immune functions.

• Dimeric structure: As IL17B functions as a dimer, antibodies must be designed to either prevent dimerization or block the active site of the dimeric form .

• Disease context: Given IL17B's involvement in conditions like spondyloarthropathy and neuronitis , the antibody design should consider tissue-specific effects and potential compensatory mechanisms.

How can researchers differentiate between IL17B-specific effects and redundant IL-17 family functions in experimental systems?

Distinguishing IL17B-specific effects from general IL-17 family functions requires multifaceted experimental approaches:

• Receptor specificity: Use receptor-specific blocking antibodies or soluble receptor constructs to differentiate signaling through IL17B receptor versus other IL-17 receptors .

• Genetic approaches: Employ CRISPR-Cas9 or siRNA to selectively knock down IL17B or its receptor in cell models, comparing results with knockdowns of other IL-17 family members.

• Combinatorial cytokine treatments: Assess cellular responses to IL17B alone versus combinations with other IL-17 family cytokines to identify synergistic, additive, or antagonistic effects.

• Pathway analysis: Utilize phosphoproteomic approaches to map signaling events downstream of IL17B and compare with other IL-17 family members to identify shared and distinct pathways.

• Transcriptomic profiling: Analyze gene expression changes induced by IL17B versus other IL-17 family cytokines to identify unique transcriptional signatures.

What are the critical quality control parameters when working with recombinant IL17B in research?

When working with recombinant IL17B, researchers should implement rigorous quality control measures:

How should researchers design experiments to investigate IL17B's role in specific inflammatory diseases?

Designing robust experiments to investigate IL17B's role in inflammatory diseases requires careful consideration of multiple factors:

• Disease-relevant cell types: Select experimental models that incorporate the principal cell types implicated in specific diseases, such as:

  • Synoviocytes and chondrocytes for spondyloarthropathy research

  • Neuronal cells for neuronitis studies

  • Epithelial cells for inflammatory bowel disease or respiratory conditions

• Physiologically relevant concentrations: Titrate IL17B concentrations to reflect levels observed in patient samples from the disease of interest.

• Temporal dynamics: Design time-course experiments to capture both acute and chronic effects of IL17B signaling.

• Combined cytokine environments: Include other inflammatory mediators known to be present in the disease microenvironment to model complex cytokine networks.

• Translational validation: Correlate in vitro findings with patient-derived samples or animal models of disease to establish clinical relevance.

How does IL17B contribute to inflammatory pathways differently from other IL-17 family cytokines?

IL17B exhibits distinct contributions to inflammatory processes compared to other IL-17 family members:

• Receptor engagement: IL17B signals exclusively through the IL17B receptor, not the IL17 receptor used by IL17A and IL17F, activating potentially different downstream pathways .

• Cellular sources: While IL17A is primarily produced by activated CD4+ T cells distinct from Th1 or Th2 cells, IL17B expression patterns appear more diverse, potentially enabling tissue-specific inflammatory responses .

• Signaling networks: IL17B is linked to mucin expression in cystic fibrosis via IL-6 and STAT3 pathways, representing a more specialized inflammatory mechanism compared to the broader pro-inflammatory effects of IL17A .

• Disease associations: IL17B is specifically associated with spondyloarthropathy and neuronitis, suggesting distinct pathological roles compared to IL17A's broader involvement in multiple autoimmune conditions .

What is the current understanding of IL17B's role in rheumatological conditions versus neuroinflammatory disorders?

Research suggests differential roles for IL17B across disease categories:

Rheumatological Conditions:

• In spondyloarthropathy, IL17B may contribute to joint inflammation and bone remodeling through mechanisms distinct from IL17A .

• IL17B appears to function within STAT3-dependent pathways that are crucial for inflammatory arthritis progression .

• Unlike IL17A and IL17F, which directly affect cartilage matrix degradation, IL17B's effects on joint tissues may involve indirect mechanisms through secondary inflammatory mediators.

Neuroinflammatory Disorders:

• IL17B's designation as a "Neuronal interleukin-17-related factor" (NIRF) suggests specialized functions in the nervous system .

• In neuronitis, IL17B may affect neuronal-glial interactions and contribute to peripheral nerve inflammation through mechanisms that differ from central nervous system inflammation associated with IL17A .

• The neuronal expression of IL17B suggests potential roles in neuroimmune communication that are not typical of other IL-17 family cytokines.

How do the structural and functional properties of IL17B compare with other IL-17 family cytokines?

The following table presents a comparative analysis of key properties across selected IL-17 family members:

This comparative analysis highlights IL17B's distinct properties within the IL-17 family, particularly its unique receptor specificity and disease associations.

What cellular responses are uniquely induced by IL17B compared to other IL-17 family cytokines?

IL17B elicits several cellular responses that differentiate it from other IL-17 family members:

• Cytokine induction profile: While all IL-17 family cytokines induce pro-inflammatory mediators, IL17B may preferentially induce specific cytokine patterns distinct from the IL-6, IL-8, and G-CSF profile strongly associated with IL17A and IL17F .

• Target cell specificity: Due to its distinct receptor binding profile, IL17B likely targets a different cellular repertoire compared to IL17A and IL17F, potentially explaining its more specific disease associations .

• Intracellular signaling: Although IL-17 family members generally activate NF-κB and MAPK pathways, IL17B appears to have stronger associations with STAT3 signaling pathways compared to other family members .

• Interaction with non-immune cells: IL17B's designation as a neuronal factor suggests unique interactions with the nervous system that are not characteristic of other IL-17 family cytokines .