C-10 Mouse

What is C-10 chemokine and what distinguishes it from other chemokines in mouse models?

C-10 is a C-C chemokine involved in the chronic stages of host defense reactions. Unlike other C-C chemokines, C-10 displays distinctive structural and functional characteristics. Structurally, C-10 shares amino acid sequence homology with several CCR1-binding chemokines but is larger due to a unique second exon in its genomic structure. This extra exon is necessary for C-10's biological activity .

From a functional perspective, C-10 shows different induction patterns compared to many chemokines. It is IL-4 inducible but not LPS inducible in macrophages, suggesting involvement in specific immune pathways. Additionally, C-10 production by various cell populations typically peaks between 24-48 hours after cytokine stimulation, indicating a role in the resolution phase rather than the initial inflammatory response .

How do C-10 levels change during infection in mouse models?

During infections such as septic peritonitis induced by cecal ligation and puncture (CLP), C-10 levels in the peritoneal cavity increase approximately 30-fold above baseline at 48 hours post-surgery. This is significantly delayed compared to other chemokines that typically peak earlier in the infection process .

This delayed expression pattern aligns with C-10's suspected role in disease resolution rather than initial inflammatory responses. The kinetics of C-10 expression should be carefully considered when designing experiments to study its function, as sampling too early might miss peak concentrations .

What experimental methods are recommended for measuring C-10 expression in mouse tissues?

For accurate measurement of C-10 expression in mouse tissues, the following methodological approaches are recommended:

• ELISA assays: Using validated anti-C10 polyclonal antibodies in direct ELISA allows quantification of C-10 protein levels in tissue homogenates or biological fluids.

• Peritoneal wash sampling: For peritoneal inflammation models, collecting wash samples at 24-48 hours post-intervention provides optimal detection of C-10 .

• Quality control measures: Researchers should verify antibody specificity by direct ELISA and ensure endotoxin content in reagents is below detection limits (<0.05 EU/ml) using appropriate tests (e.g., PYROGENT) .

• Timing considerations: Given C-10's delayed expression pattern, sampling at multiple timepoints (particularly 24-48 hours after stimulation) is essential for capturing peak levels .

What is the relationship between C-10 and bacteremia in mouse models of sepsis?

C-10 administration significantly impacts bacteremia in mouse models of sepsis, with experimental evidence showing that C-10 therapy substantially reduces bacterial dissemination. At 24 hours after CLP surgery, only 25% of C-10-treated mice exhibited bacteremia compared to 85% of the control group .

This reduction in bacteremia appears to be mediated through multiple mechanisms:

• Enhanced phagocytic activity: C-10 significantly improves the bacterial phagocytic capacity of peritoneal macrophages .

• Improved gut barrier function: C-10 therapy reduces leakage of material from the damaged intestine during septic peritonitis, limiting bacterial translocation .

• Coordinated cytokine responses: C-10 facilitates rapid enhancement of TNF-α and MCP-1 levels followed by later increases in IL-13, potentially orchestrating effective bacterial clearance while controlling inflammation .

What are the optimal parameters for C-10 administration in mouse experimental models?

Based on experimental evidence, the following administration parameters have demonstrated efficacy in mouse models:

These parameters were determined through dose-finding studies which revealed that 500 ng represented the minimum effective dose for significant survival effects following CLP surgery. The lack of additional benefit with higher doses suggests potential receptor saturation or maximum biological effect at this dose level .

How does C-10 modulate the cytokine network in mouse infection models?

C-10 exerts complex effects on the cytokine network during infection, functioning as both a response to and a modulator of other immune mediators:

• Effects on pro-inflammatory cytokines: C-10 therapy rapidly enhances levels of TNF-α and MCP-1 in the peritoneal cavity .

• Interaction with IL-1β: The combination of IL-1β and C-10 synergistically augments TNF-α synthesis by peritoneal macrophages .

• Relationship with IL-13: C-10 administration leads to later increases in IL-13 levels. Conversely, IL-13 can induce C-10 synthesis in peritoneal macrophages, suggesting a positive feedback loop .

• IL-4 dependency: Unlike many chemokines, C-10 production requires IL-4 stimulation in macrophages, connecting it to Th2-type immune responses .

This immunomodulatory profile positions C-10 as a potential orchestrator of the transition from pro-inflammatory to resolution phases of the immune response.

What phenotypic differences are observed between C-10-deficient and wild-type mice during infection?

The immunoneutralization of endogenous C-10 during CLP-induced peritonitis provides insights into the phenotypic consequences of C-10 deficiency. Mice receiving anti-C-10 antiserum approximately 2 hours prior to CLP surgery showed significantly reduced survival over 4 days compared to controls receiving normal rabbit preimmune serum .

This survival disadvantage suggests several potential phenotypic differences in C-10-deficient conditions:

• Impaired bacterial clearance, likely due to reduced macrophage phagocytic activity.

• Increased bacterial dissemination from the primary infection site.

• Dysregulated cytokine responses affecting both pro-inflammatory and resolution phases.

• Compromised intestinal barrier function during peritonitis .

These observations highlight C-10's non-redundant role in host defense during septic peritonitis and suggest that genetic C-10 deficiency might similarly impair infection resolution.

What mouse strains are most appropriate for studying C-10 function?

While the provided research doesn't specifically compare C-10 function across different mouse strains, important methodological considerations can be derived from broader mouse model research:

The majority of experimental mouse work is conducted on C57BL/6 background strains, with over 98% of genetically-modified mouse lines in large-scale screening studies using this core strain . For C-10 research specifically, studies demonstrating its role in septic peritonitis have successfully used this background.

When selecting mouse strains for C-10 research, researchers should consider:

• Genetic background consistency: Maintaining consistent genetic backgrounds is critical, as immune responses vary significantly between strains.

• Age standardization: Combining mice with a ±2-week age difference for analysis represents standard practice .

• Viability considerations: When studying genetic modifications affecting C-10, researchers should note that approximately 21.7% of mutant alleles in large-scale studies are lethal and 7.3% subviable, which may necessitate heterozygote analysis .

What are the critical quality control measures for C-10 research in mouse models?

Implementing rigorous quality control measures is essential for reliable C-10 research:

• Antibody validation: Anti-C-10 polyclonal antibodies must be titrated and verified for specificity by direct ELISA .

• Endotoxin testing: All reagents, including recombinant C-10, preimmune serum, and anti-C-10 antiserum, should be confirmed to have endotoxin content below detection limits (<0.05 EU/ml) .

• Technical procedure documentation: Note any technical issues during experimental procedures (such as difficulties in locating veins during injection) as potential confounding factors .

• Operator consistency: The same individual should perform critical procedures to minimize variation due to operator effects .

• Control distribution: For large experimental groups, include control animals at the beginning, middle, and end of the procedure to detect potential time-dependent variations .

How should researchers design dose-response studies for C-10 in mouse models?

Based on existing methodological approaches, researchers should consider the following design elements for C-10 dose-response studies:

• Dose range selection: Begin with a range that includes 500 ng as a reference point, since this dose showed significant effects in CLP models. Include both lower doses to establish the minimum effective dose and higher doses (e.g., 1-2 μg) to identify potential plateau effects .

• Administration timing: Since immediate post-CLP administration showed significant benefits, time-course studies should include this timepoint plus delayed administration to determine the therapeutic window .

• Outcome measures: Include both survival (primary outcome in previous studies) and mechanistic endpoints such as:

  • Bacterial clearance and dissemination

  • Cytokine production profiles

  • Macrophage phagocytic activity

  • Tissue damage markers

• Control groups: Include both vehicle controls (normal saline) and groups receiving related chemokines to establish specificity of effects .

How does the mouse C-10 response compare to analogous chemokine responses in humans?

While the search results don't directly address human correlates of mouse C-10, this represents an important translational research question. Researchers should consider:

• The human chemokine system shares many homologies with mice, but important species-specific differences exist in expression patterns and receptor utilization.

• The mouse C-10 delayed expression pattern (peaking at 24-48 hours) and IL-4 dependency may have implications for identifying the most relevant human counterparts .

• The efficacy of C-10 in reducing bacteremia and enhancing macrophage phagocytic function in mouse models suggests potential translational targets in human sepsis therapy .

Comparative studies examining chemokine expression kinetics in mouse models alongside human samples from comparable disease states would help establish appropriate translational pathways.

What experimental approaches can test C-10's therapeutic potential in diverse mouse disease models?

Beyond septic peritonitis, researchers can explore C-10's therapeutic potential in multiple disease contexts using these approaches:

• Mouse-adapted infection models: The mouse-adapted SARS-CoV-2 MA10 strain approach demonstrates how infection models can be modified for mouse studies . Similar adaptations could be applied to study C-10's role in viral infections.

• Experimental metastasis models: The B16-F10 pulmonary metastasis model, where mice are tail vein dosed with 4-5×10^5 cells, could be adapted to investigate C-10's impact on cancer metastasis, given its immunomodulatory properties .

• Genetic approaches: The genome-wide screening methodologies using genetically-modified mouse lines could be applied to identify genetic factors that interact with C-10 pathways .

• Combination therapy protocols: Given C-10's enhancement of TNF-α synthesis when combined with IL-1β, structured studies of C-10 in combination with other immunomodulatory agents could reveal synergistic therapeutic approaches .

What are the key considerations for planning C-10 mouse studies?

When planning C-10 mouse studies, researchers should consider:

• Temporal dynamics: C-10 peaks 24-48 hours after stimulation, requiring appropriate sampling timepoints .

• Dose selection: 500 ng represents an effective dose in CLP models, with higher doses showing plateau effects .

• Control selection: Include both vehicle controls and ideally controls for related chemokines to establish specificity.

• Strain consistency: Maintain genetic background consistency, with C57BL/6 strains being well-established for immunological studies .

• Outcome measures: Include both survival outcomes and mechanistic endpoints such as bacterial clearance, cytokine profiles, and phagocytic activity.

• Quality control: Implement rigorous quality control for reagents, techniques, and experimental procedures .