RETNLB (Resistin-like beta) antibodies are specialized immunological tools designed to detect and study the RETNLB protein, a member of the Resistin/FIZZ family. RETNLB is a 111-amino-acid, 11.7-kDa secreted protein predominantly expressed in the gastrointestinal tract, particularly the colon . It is implicated in inflammation, metabolism, and cancer progression. These antibodies are critical for research in oncology, immunology, and gastrointestinal diseases, enabling techniques like Western blot (WB), ELISA, and immunohistochemistry (IHC) .
Protein Structure: RETNLB is a cysteine-rich protein with a canonical secretory pathway . It exhibits orthology in mice, rats, and chimpanzees .
Biological Role: While exact functions are debated, RETNLB is hypothesized to act as a hormone regulating intestinal inflammation and tumor growth . In colorectal cancer (CRC), its expression correlates inversely with tumor progression grade .
Expression Patterns: RETNLB levels are significantly reduced in CRC biopsies compared to healthy tissue (p < 0.01) . Low expression correlates with advanced TNM grades (p < 0.001) and poor 5-year survival (71.86% high vs. 28.14% low expression) .
Mechanism: RETNLB modulates the TLR2/4/ERK pathway, influencing tumor growth and immune evasion .
Prognosis: High RETNLB expression predicts poor survival (HR = 2.15, p < 0.05) . Knockdown experiments reveal its role in promoting cell proliferation and migration .
RETNLB (resistin like beta) is a secreted protein encoded by the RETNLB gene in humans. It consists of 111 amino acid residues with a molecular weight of approximately 12 kDa and functions as an intestinal goblet cell-specific protein that becomes notably upregulated during intestinal inflammation . The significance of RETNLB in research spans multiple areas, including inflammatory diseases, cancer biology (particularly in gastrointestinal and oral cancers), and metabolic function studies . Recent research has revealed that RETNLB may play a crucial role in modulating hepatic insulin action, as infusions of RETNLB in experimental models have been shown to induce severe hepatic insulin resistance and stimulate hepatic glucose production through increased flux via glucose-6-phosphatase .
RETNLB antibodies are valuable research tools employed in multiple experimental techniques:
Immunohistochemistry (IHC): Used to detect and localize RETNLB expression in tissue samples, with particular utility in studying gastrointestinal tissues and cancer specimens .
Western Blot: Applied to determine RETNLB protein expression levels in cell and tissue lysates .
ELISA: Used for quantitative measurement of RETNLB in biological samples .
These applications enable researchers to investigate RETNLB expression patterns, regulation mechanisms, and potential roles in pathophysiological processes across different experimental systems.
When selecting a RETNLB antibody for research, consider these critical specifications:
The optimal antibody selection should align with your specific experimental objectives, sample types, and detection methods.
For optimal immunohistochemical detection of RETNLB in tissue specimens:
Tissue Preparation:
Fix tissues in 10% neutral buffered formalin
Process and embed in paraffin
Section at 4-6μm thickness
Antigen Retrieval:
Antibody Incubation:
Detection System:
Counterstaining and Mounting:
Hematoxylin counterstaining
Dehydration and mounting with appropriate medium
The protocol may require optimization based on tissue type, fixation conditions, and specific antibody characteristics. Titration experiments are recommended to determine optimal dilution for your specific system .
A robust experimental design with RETNLB antibodies requires several controls:
Positive Controls:
Human liver cancer tissue (demonstrated positive reactivity)
Cell lines with confirmed RETNLB expression (e.g., CAL27 and TCA-83 oral squamous cell carcinoma lines)
Negative Controls:
Antibody diluent without primary antibody on target tissue
Isotype control (non-specific rabbit IgG at same concentration)
Tissues known to lack RETNLB expression
Cells with RETNLB knockdown (e.g., si-RETNLB transfected cells)
Method Validation Controls:
Serial dilution of primary antibody to establish optimal concentration
Preabsorption with immunizing peptide to confirm specificity
Western blot analysis to confirm antibody specificity by molecular weight
Expression Modulation Controls:
In vitro RETNLB knockdown models using siRNAs (for functional studies)
Recombinant RETNLB protein standards (for quantitative applications)
Including these controls helps validate antibody specificity, optimize experimental conditions, and support the reliability of experimental findings.
Proper storage and handling of RETNLB antibodies is critical for maintaining their performance:
Storage Conditions:
Avoid repeated freeze-thaw cycles
Antibodies are typically supplied in PBS pH 7.3 with 50% glycerol and 0.02-0.05% sodium azide as preservative
Stability:
Most RETNLB antibodies remain stable for one year from the date of receipt when properly stored
Aliquoting is generally unnecessary for -20°C storage due to the glycerol content
Working Solution Preparation:
Thaw antibody completely before use
Mix gently by inversion or pipetting (avoid vortexing)
Briefly centrifuge to collect solution at bottom of tube
Prepare working dilutions fresh before use
Return stock solution to -20°C immediately after use
Safety Considerations:
Handle with appropriate PPE due to sodium azide content
Properly dispose of antibody-containing waste according to local regulations
Quality Indicators:
Solution should be clear without visible precipitates
If precipitation occurs, incubate at room temperature and mix gently
If performance decreases, replace with fresh aliquot
Following these guidelines will help maximize antibody performance and extend shelf life.
Research using RETNLB antibodies has revealed significant correlations between RETNLB expression and cancer progression, particularly in oral squamous cell carcinoma (OSCC):
These findings indicate RETNLB may serve as a potential biomarker for cancer progression and as a therapeutic target, particularly in oral, gastric, and colorectal malignancies.
To investigate RETNLB's functions in inflammatory processes, researchers employ several methodological approaches:
Expression Analysis in Inflammatory Conditions:
Functional Modulation Studies:
Signaling Pathway Analysis:
Gene Expression Profiling:
Cell-Specific Expression Studies:
Co-localization IHC using RETNLB antibodies alongside markers for inflammatory cell types
Flow cytometry analysis of RETNLB expression in specific immune cell populations
These approaches provide complementary insights into how RETNLB contributes to inflammatory processes at molecular, cellular, and tissue levels.
RETNLB antibodies provide valuable tools for investigating metabolic pathways, particularly relating to insulin resistance and glucose metabolism:
Tissue Expression Profiling:
IHC analysis of RETNLB expression in metabolic tissues (liver, adipose, gastrointestinal tract)
Correlation of expression patterns with metabolic parameters in animal models and clinical samples
Glucose Metabolism Studies:
Signaling Pathway Interrogation:
Western blot analysis of insulin signaling components (IRS, PI3K, AKT) in response to RETNLB modulation
Phosphorylation status assessment in metabolic signaling cascades
Functional Assessment in Metabolic Cell Models:
Detection of RETNLB in conditioned media from relevant cell types
Analysis of glucose uptake, glycogen synthesis, and lipid metabolism following RETNLB treatment
Investigation of cross-talk between RETNLB and other metabolic hormones
In Vivo Metabolic Phenotyping:
Correlation of RETNLB protein levels with:
Glucose tolerance test parameters
Insulin resistance indices
Hepatic glucose output measurements
Lipid profiles
Receptor Identification Studies:
Co-immunoprecipitation with RETNLB antibodies to identify binding partners
Immunofluorescence co-localization studies to visualize receptor interactions
These approaches help elucidate RETNLB's role in the regulation of glucose metabolism and insulin action, particularly in the context of metabolic disorders.
When working with RETNLB antibodies, researchers may encounter several sources of non-specific staining, which can be addressed through specific optimization strategies:
For RETNLB-specific optimization:
Validate antibody specificity using known positive controls (human small intestine tissue)
Include a negative control by omitting primary antibody
Consider using recombinant RETNLB protein for pre-absorption controls
For IHC applications, carefully follow recommended antigen retrieval protocols specific for RETNLB detection
Through systematic optimization of these parameters, researchers can significantly improve the signal-to-noise ratio when using RETNLB antibodies.
Inconsistent RETNLB detection across experimental systems is a common challenge that can be addressed through systematic troubleshooting:
Sample Preparation Variables:
Fixation conditions: Standardize fixation protocols (time, temperature, fixative)
Tissue processing: Ensure consistent processing methods across samples
Storage conditions: Monitor sample storage duration and temperature
Antibody-Related Factors:
Antibody lot variation: Test new lots against previous reference samples
Concentration optimization: Perform titration for each experimental system
Incubation conditions: Standardize time, temperature, and humidity
Technical Considerations:
Biological Variability:
Expression heterogeneity: Use multiple fields/replicates to account for heterogeneous expression
Developmental/physiological status: Control for age, disease state, and treatment conditions
Cell type specificity: RETNLB is primarily expressed in intestinal goblet cells; confirm appropriate cell populations are present
Verification Approaches:
Multiple antibody validation: Test with alternative antibodies targeting different RETNLB epitopes
Complementary techniques: Confirm findings with orthogonal methods (e.g., qRT-PCR, Western blot)
Positive controls: Include standardized positive controls (e.g., human small intestine tissue or human liver cancer tissue)
By systematically addressing these factors, researchers can identify sources of variability and establish reproducible protocols for RETNLB detection across experimental systems.
Detecting low-abundance RETNLB expression requires optimized protocols to enhance sensitivity without compromising specificity:
Signal Amplification Techniques:
Tyramide signal amplification (TSA): Can enhance detection sensitivity 10-100 fold
Polymer-based detection systems: Provide higher sensitivity than traditional ABC methods
Multiple-step detection: Sequential amplification steps for ultra-sensitive detection
Antibody Optimization:
Sample Preparation Refinements:
Detection Method Selection:
Chromogenic vs. fluorescent: Fluorescent detection often provides better sensitivity
Digital imaging: Utilize high-resolution imaging and signal quantification
Automated platforms: Consider standardized automated IHC platforms for consistent results
Enrichment Strategies:
When detecting low-abundance RETNLB, it's essential to include appropriate positive controls and implement rigorous optimization to distinguish true signal from background.
RETNLB antibodies offer significant potential in cancer biomarker development, particularly for gastrointestinal and oral cancers:
Tissue Microarray Analysis:
IHC screening of large patient cohorts with standardized RETNLB antibody protocols
Correlation of expression patterns with clinicopathological parameters
Development of scoring systems based on staining intensity and distribution
Prognostic Biomarker Validation:
Liquid Biopsy Development:
ELISA-based detection of circulating RETNLB in patient serum/plasma
Correlation of levels with disease stage, progression, and treatment response
Longitudinal monitoring for early detection of recurrence
Therapeutic Target Identification:
Companion Diagnostic Development:
Identification of RETNLB expression thresholds that predict response to specific therapies
Development of standardized IHC protocols for clinical implementation
Integration with other molecular markers for comprehensive profiling
Technical Implementation:
Adaptation of research-grade antibodies for clinical diagnostic applications
Validation across multiple laboratories to ensure reproducibility
Automation of staining protocols for clinical implementation
The research showing that RETNLB knockdown significantly reduces cancer cell viability, mobility, and invasiveness demonstrates its potential as both a biomarker and therapeutic target .
RETNLB antibodies are enabling several cutting-edge research applications that illuminate disease mechanisms:
Single-Cell Analysis:
Integration with single-cell technologies to map RETNLB expression at cellular resolution
Identification of specific cell populations with altered RETNLB expression in disease states
Correlation with single-cell transcriptomics to identify co-expression patterns
Spatial Biology Applications:
Multiplex immunofluorescence to simultaneously visualize RETNLB with other markers
Spatial transcriptomics combined with protein detection to map expression landscapes
Analysis of RETNLB expression in tissue microenvironments (tumor-stroma interfaces, inflammatory foci)
Pathway Interaction Mapping:
Dynamic Expression Studies:
Live-cell imaging with fluorescently-tagged antibody fragments
Temporal analysis of RETNLB expression during disease progression
Correlation with metabolic and inflammatory markers in real-time
Translational Research Applications:
Patient-derived organoid models to study RETNLB function in personalized contexts
Drug screening platforms incorporating RETNLB as a response biomarker
Development of RETNLB-targeting therapeutic modalities based on antibody specificity
Cross-Disease Comparisons:
These emerging applications leverage RETNLB antibodies to build comprehensive understanding of disease mechanisms, potentially leading to novel diagnostic and therapeutic strategies.
The integration of gene editing technologies with RETNLB antibody-based detection offers powerful approaches for mechanistic investigations:
CRISPR/Cas9 Knockout and Knockin Models:
Generate RETNLB knockout cell lines and animal models
Create reporter knockins (fluorescent tags, epitope tags) for live tracking
Use RETNLB antibodies to validate editing efficiency by Western blot/IHC
Compare protein expression patterns between wild-type and edited models
Domain-Specific Functional Analysis:
Engineer truncation or point mutations in RETNLB functional domains
Use RETNLB antibodies to assess expression, localization, and stability of mutants
Correlate structural modifications with functional outcomes (secretion, receptor binding)
Regulatory Element Editing:
CRISPR-mediated modification of RETNLB promoter/enhancer regions
Analyze consequent changes in protein expression using antibody-based detection
Map regulatory networks controlling RETNLB expression in different tissues
Pathway Validation Studies:
Temporal Control Systems:
Implement inducible CRISPR systems for temporal regulation of RETNLB
Track expression dynamics using antibody-based methods
Correlate with phenotypic changes in metabolism or inflammatory responses
High-Throughput Screening:
Combine genome-wide CRISPR screens with RETNLB antibody detection
Identify novel regulators of RETNLB expression and function
Validate hits through targeted editing and quantitative antibody-based assays
This integrated approach provides mechanistic insights into RETNLB function that cannot be achieved through either technique alone, offering a powerful toolset for investigating RETNLB's roles in inflammation, metabolism, and cancer biology.
RETNLB expression exhibits distinctive patterns across tissue types, requiring careful consideration of detection methods and interpretation:
Interpretation Challenges:
Cellular Heterogeneity: RETNLB expression may be restricted to specific cell subtypes within tissues
Baseline Variability: Normal expression levels vary significantly between tissue types
Context-Dependent Regulation: Expression patterns change during inflammation or malignant transformation
Methodological Recommendations:
Include appropriate positive controls (small intestine) with each experiment
Evaluate multiple fields and regions within each tissue sample
Use specific cell type markers in dual-labeling experiments to identify RETNLB-expressing cells
Consider quantitative analysis methods to objectively compare expression levels across tissues
Standardize all technical parameters (antibody dilution, incubation time, detection system) when comparing across tissue types
This comparative approach enables reliable assessment of normal versus pathological RETNLB expression across diverse tissue contexts.
Discrepancies between RETNLB mRNA and protein expression levels are common and require careful interpretation:
Potential Mechanisms for Discordance:
Post-transcriptional regulation (miRNAs, RNA-binding proteins)
Translational efficiency variations
Protein stability and turnover differences
Secretion of RETNLB protein from cells (reducing intracellular detection)
Technical variations in detection methodologies
Methodological Considerations:
mRNA detection: qRT-PCR or RNA-Seq measure transcript abundance
Protein detection: Antibody-based methods (Western blot, IHC, ELISA) detect protein levels
Each technique has different sensitivity, specificity, and dynamic range
Integrated Analysis Approach:
Perform parallel mRNA and protein analysis on the same samples
Use multiple methodologies to confirm expression patterns
Consider temporal dynamics (mRNA changes may precede protein changes)
Account for subcellular localization and secretion of RETNLB
Functional Validation Strategies:
Manipulate expression (knockdown/overexpression) and measure consequences at both mRNA and protein levels
In OSCC studies, si-RETNLB reduced both mRNA and protein levels, confirming successful targeting
Correlate expression changes with functional outcomes (proliferation, invasion, signaling activation)
Interpretation Framework:
High mRNA/Low protein: Consider protein degradation, inefficient translation, or active secretion
Low mRNA/High protein: Consider protein stability, post-transcriptional regulation, or technical artifacts
Concordant changes: Stronger evidence for biologically significant regulation
This integrated approach helps researchers distinguish between technical artifacts and biologically meaningful expression patterns when studying RETNLB in disease contexts.
Advanced computational methods significantly enhance the depth and rigor of RETNLB antibody-based research:
Digital Pathology and Image Analysis:
Automated quantification of RETNLB IHC staining intensity and distribution
Machine learning algorithms for pattern recognition in tissue samples
Multiplexed image analysis for co-expression studies with other markers
Whole slide imaging for comprehensive tissue analysis beyond selected fields
Multi-Omics Data Integration:
Network Analysis Approaches:
Protein-protein interaction mapping based on co-immunoprecipitation data
Pathway enrichment analysis to contextualize RETNLB in signaling networks
Identification of RETNLB-centered regulatory modules in disease states
Network-based drug target identification
Predictive Modeling:
Machine learning models to predict patient outcomes based on RETNLB expression
Development of integrated biomarker signatures incorporating RETNLB
In silico screening for compounds that may modulate RETNLB expression or function
Spatial Transcriptomics Integration:
Correlation of antibody-detected protein localization with spatial transcriptomics data
Cell type deconvolution in complex tissues
Microenvironment analysis in disease contexts
Antibody Specificity Computational Validation:
Epitope prediction algorithms to assess potential cross-reactivity
Structural modeling of antibody-antigen interactions
Database mining to identify proteins with similar epitopes
These computational approaches transform antibody-based detection from qualitative observation to quantitative, mechanistic insights that can guide hypothesis generation and experimental design in RETNLB research.