The LPP (Lipoma-preferred partner) antibody conjugated with fluorescein isothiocyanate (FITC) is a fluorescently labeled reagent designed for detecting the LPP protein, a scaffolding protein involved in cell adhesion, motility, and transcriptional regulation . FITC conjugation enables visualization via fluorescence microscopy, flow cytometry, or immunoblotting, leveraging FITC’s excitation/emission peaks at 495 nm/525 nm . This antibody is widely used in biomedical research to study LPP’s role in cancer, cardiovascular biology, and cellular dynamics .
Cancer Studies: Detects LPP overexpression in lung, mammary, and rectal cancer tissues via IHC .
Cardiac Research: Labels LPP in mouse and rat cardiac muscle sections, aiding studies on heart disease .
Cell Motility Assays: Tracks LPP dynamics in focal adhesions during wound healing or metastasis .
Immunofluorescence: Demonstrated in A431 cells using DyLight®488 secondary antibodies .
IHC Validation:
Cross-Reactivity: No background observed in CHO cells or untagged proteins .
Perform heat-mediated antigen retrieval in EDTA buffer (pH 8.0).
Block with 10% goat serum.
Incubate with 1 µg/mL FITC-conjugated LPP antibody overnight at 4°C .
Detect using biotinylated secondary antibodies and SABC-DAB .
LPP (Lipoma-preferred partner homolog) is a multifunctional protein that plays a structural role at cell adhesion sites, maintaining cell shape and motility. Beyond these structural functions, LPP is implicated in signaling events and gene transcription activation. Its significance stems from its involvement in signal transduction from cell adhesion sites to the nucleus, enabling successful integration of signals from soluble factors and cell-cell adhesion sites. LPP also serves as a scaffold protein upon which distinct protein complexes assemble in both cytoplasm and nucleus . Recent studies have identified LPP as a potential biomarker for treatment response in gastric cancer, making it increasingly relevant for cancer research and immunotherapy investigations .
LPP Antibody (FITC) is a rabbit polyclonal antibody specific to LPP with the following technical specifications:
| Parameter | Specification |
|---|---|
| Category | Primary Antibodies |
| Immunogen Target | Lipoma-preferred partner homolog (LPP) |
| Host | Rabbit |
| Reactivity | Human |
| Clonality | Polyclonal |
| Conjugation | FITC (Fluorescein isothiocyanate) |
| Isotype | IgG |
| Purity | > 95% |
| Purification Method | Protein G |
| Form | Liquid |
| Buffer Composition | 0.01 M PBS, pH 7.4, 0.03% Proclin-300, 50% Glycerol |
| Storage Requirements | Aliquot and store at -20°C; avoid light exposure and freeze/thaw cycles |
| UniProt ID | Q93052 |
| Gene ID | 4026 |
These specifications provide critical information for researchers to properly incorporate this antibody into their experimental design and protocols .
To maintain optimal functionality of LPP Antibody-FITC, researchers should follow these methodological guidelines:
Storage temperature: Aliquot the antibody and store at -20°C to prevent protein degradation .
Light protection: FITC is photosensitive, so the antibody should be protected from light during storage and handling to prevent photobleaching. Use amber tubes or wrap containers in aluminum foil .
Avoid freeze/thaw cycles: Repeated freezing and thawing can damage antibody structure and reduce fluorescence intensity. Create single-use aliquots upon receipt .
Buffer conditions: The antibody is supplied in a buffer containing 50% glycerol which helps maintain stability. Do not dilute the stock solution until ready for use .
Working temperature: When actively using the antibody, keep it on ice and in low-light conditions to minimize degradation.
Centrifugation: Briefly centrifuge the vial before opening to collect all liquid at the bottom of the tube.
Quality testing: Periodically verify the antibody's performance using positive control samples if stored for extended periods.
Following these handling procedures will help ensure consistent and reliable experimental results when using this antibody .
The primary application of LPP Antibody-FITC in basic research is for direct visualization and localization of LPP protein in cells and tissues. This antibody enables several key methodologies:
Immunofluorescence microscopy: The direct FITC conjugation allows for one-step detection of LPP in fixed cells and tissue sections. This is particularly useful for studying LPP's distribution at cell adhesion sites and in the nucleus .
Flow cytometry (FACS): The antibody can be used to quantify LPP expression levels across different cell populations, providing quantitative analysis without requiring secondary antibodies .
Cell surface protein detection: Although LPP is primarily intracellular, certain experimental systems may express recombinant LPP on cell surfaces, where this antibody can be valuable for confirming successful surface display .
Protein localization studies: The antibody allows researchers to investigate how LPP shuttles between adhesion sites and the nucleus in response to various cellular stimuli .
Co-localization experiments: When combined with other fluorescently labeled antibodies targeting different markers, LPP-FITC antibody enables studies of protein-protein interactions and complex formation .
These applications provide fundamental insights into LPP's biological roles in cellular adhesion, signaling, and gene regulation .
Designing optimal immunofluorescence protocols with LPP Antibody-FITC requires careful consideration of multiple methodological factors:
Sample preparation:
Fix cells with 3-4% paraformaldehyde to preserve cellular architecture
Permeabilize with 0.1-0.5% Triton X-100 to allow antibody access to intracellular LPP
Consider dual fixation protocols (paraformaldehyde followed by methanol) for preserving both cytoskeletal and nuclear structures
Blocking strategy:
Antibody incubation:
Begin with manufacturer's recommended dilution (optimal dilutions should be determined experimentally)
Incubate at 4°C for 4 hours or overnight in a humidified chamber
For dual labeling experiments, carefully plan fluorophore combinations to avoid spectral overlap with FITC (excitation ~495nm, emission ~520nm)
Washing protocol:
Mounting and visualization:
Controls:
Include negative controls (omitting primary antibody)
Use cells with known LPP expression patterns as positive controls
For validation, compare results with non-FITC conjugated anti-LPP antibody and compatible secondary antibody
Quantification:
Implement consistent image acquisition parameters
Use software algorithms to quantify fluorescence intensity, colocalization coefficients, or subcellular distribution patterns
This detailed protocol strategy ensures reproducible and reliable detection of LPP in diverse experimental contexts .
Flow cytometry analysis using LPP Antibody-FITC requires specific technical considerations to ensure reliable and quantitative results:
Cell preparation protocol:
Harvest cells (approximately 1×10^6 cells) at optimal density
Use gentle cell dissociation methods to maintain cellular integrity
For adherent cells expressing LPP, ensure complete dissociation to single-cell suspensions
Fixation and permeabilization:
Since LPP is primarily intracellular, use appropriate fixation (2-4% paraformaldehyde) and permeabilization (0.1% saponin or 0.1-0.5% Triton X-100) reagents
Optimize fixation time to balance epitope preservation with cellular integrity
Blocking and antibody incubation:
Flow cytometer setup:
Use appropriate laser (488 nm) and filter sets for FITC detection
Run single-color controls for proper compensation if performing multicolor analysis
Include unstained controls to establish autofluorescence baseline
Data acquisition considerations:
Collect sufficient events (minimum 10,000-20,000 cells) for statistical reliability
Set appropriate PMT voltages to ensure signal is within detection range
Record forward and side scatter parameters to distinguish viable cells
Analysis strategy:
Gate on viable single cells using FSC/SSC parameters
Analyze FITC signal intensity (mean/median fluorescence intensity) to quantify LPP expression levels
For comparison between samples, use standardized beads to calibrate fluorescence intensity
Validation controls:
Include isotype control to establish background fluorescence levels
Use positive and negative control cell lines with known LPP expression profiles
Consider using cells with LPP knockdown/overexpression as additional controls
This methodical approach ensures accurate quantification of LPP expression across different cell populations and experimental conditions .
Validating antibody specificity is crucial for ensuring experimental rigor. For LPP Antibody-FITC, implement the following comprehensive validation strategy:
Western blot analysis:
Genetic manipulation controls:
Compare signal in wild-type cells versus cells with LPP knockdown (siRNA/shRNA)
Analyze LPP-overexpressing cells to confirm increased signal intensity
Use CRISPR/Cas9-mediated knockout cells as definitive negative controls
Peptide competition assay:
Pre-incubate the antibody with excess immunizing peptide
Confirm signal reduction or elimination in subsequent detection assays
Include non-competing peptide controls to confirm specificity
Cross-reactivity assessment:
Immunoprecipitation validation:
Perform immunoprecipitation followed by mass spectrometry
Confirm LPP peptides are among precipitated proteins
Analyze for potential off-target binding partners
Multi-technique concordance:
Compare LPP detection patterns across immunofluorescence, flow cytometry, and Western blotting
Correlate protein expression with mRNA levels using qRT-PCR
Consistency across methods strengthens validation
Subcellular localization verification:
Confirm that observed LPP localization matches established patterns (adhesion sites and nucleus)
Use subcellular fractionation followed by Western blotting to verify compartment-specific distribution
This systematic validation approach ensures that experimental findings attributed to LPP detection are genuine and not artifacts of non-specific antibody binding .
Accurate quantification of fluorescence intensity when using LPP Antibody-FITC is influenced by numerous technical factors that must be carefully controlled:
Intrinsic FITC properties:
pH sensitivity: FITC fluorescence decreases at acidic pH; maintain buffers at pH 7.2-8.0
Photobleaching vulnerability: FITC loses approximately 5-10% intensity per minute of continuous exposure to excitation light
Quantum yield variations: Temperature and solvent conditions can affect fluorescence efficiency
Sample preparation influences:
Fixation method: Different fixatives (paraformaldehyde, methanol) can affect epitope accessibility and fluorophore performance
Permeabilization extent: Over-permeabilization may cause protein leakage; insufficient permeabilization limits antibody access
Autofluorescence: Cellular components (NADH, flavins, elastin) can contribute background fluorescence in the FITC spectrum
Instrumentation variables:
Excitation source stability: Fluctuations in laser/lamp intensity directly affect fluorescence measurements
Detector sensitivity: PMT voltage settings alter signal amplification; standardize between experiments
Optical path: Lens quality, cleanliness, and alignment impact light collection efficiency
Acquisition parameters:
Exposure time: Must be standardized across compared samples
Dynamic range: Avoid pixel saturation which prevents accurate intensity comparisons
Z-stack sampling: For 3D specimens, consistent z-step size and range are essential
Analytical considerations:
Background subtraction methods: Different approaches yield varying results
Segmentation algorithms: Cell/nuclear boundary definition affects intensity measurements
Normalization strategies: Choose appropriate reference standards (internal controls, calibration beads)
Biological variables:
Cell cycle stage: LPP expression and localization may vary throughout the cell cycle
Cell density effects: Contact inhibition may alter LPP expression and distribution
Sample heterogeneity: Mixed cell populations require careful gating or image segmentation
To achieve reliable quantification, researchers should implement standardized protocols with appropriate controls, calibration standards, and statistical methods for comparing fluorescence intensities across experimental conditions .
Recent research has revealed important correlations between LPP expression and immunotherapy response, which can be methodically investigated using LPP Antibody-FITC techniques:
Clinical correlations with immunotherapy:
Lower LPP expression has been observed in gastric cancer patients responsive to anti-PD1 therapy compared to non-responders
High LPP expression correlates with higher Tumor Immune Dysfunction and Exclusion (TIDE) scores, predicting poorer response to immune checkpoint blockade
Similar trends have been observed in melanoma patients, suggesting a potentially broader role across cancer types
Methodological approaches using LPP Antibody-FITC:
a) Tissue microarray analysis:
Apply LPP Antibody-FITC to tissue microarrays from patient cohorts with known immunotherapy response data
Quantify LPP expression levels and correlate with clinical outcomes
Implement multi-parameter analysis incorporating T-cell markers
b) Flow cytometric profiling:
Use LPP Antibody-FITC in combination with immune cell markers (CD4, CD8, CD45)
Analyze relationships between LPP expression and T-cell subtype distribution
Sort cell populations based on LPP expression for further functional studies
c) In vitro immune co-culture systems:
Label tumor cells or fibroblasts with LPP Antibody-FITC
Co-culture with immune cells and assess functional responses
Measure cytokine production, T cell activation, and tumor cell killing
Mechanism investigation:
Translational implementation:
Develop standardized LPP quantification protocols for potential biomarker use
Establish threshold values for predicting immunotherapy response
Combine with other predictive markers for enhanced patient stratification
Data analysis approach:
Implement machine learning algorithms to identify complex patterns
Construct multivariate models incorporating LPP expression and immune parameters
Validate findings across independent patient cohorts
This research direction provides valuable insights for patient stratification and personalized immunotherapy approaches, potentially improving treatment outcomes in various cancer types .
Successful multiplexed imaging with LPP Antibody-FITC alongside other fluorescent markers requires specific protocol modifications to achieve clear signal separation and minimize artifacts:
Fluorophore selection and combination strategy:
Choose complementary fluorophores with minimal spectral overlap with FITC (Ex: 495nm, Em: 520nm)
Recommended combinations include FITC/TRITC/DAPI or FITC/Cy5/DAPI
Avoid fluorophores with significant bleed-through into the FITC channel (e.g., GFP, YFP)
Sequential staining approach:
For directly conjugated antibodies, apply in order of increasing wavelength to reduce photobleaching effects
When combining with non-conjugated antibodies requiring secondaries, optimize blocking steps between rounds
Antibody dilution and interaction considerations:
Re-optimize antibody dilutions when used in combination (often requiring higher dilutions)
Test for potential cross-reactivity between antibodies from the same species
Consider antibody isotype and subclass to avoid detection conflicts
Microscopy setup parameters:
Implement sequential scanning mode rather than simultaneous acquisition
Configure channel-specific laser power and detector sensitivity settings
Utilize narrow bandpass filters to minimize spectral overlap
Advanced controls for multiplexed imaging:
Single-stained controls for each fluorophore to establish baseline signals
Fluorescence minus one (FMO) controls to accurately set gates/thresholds
Include absorption controls to detect and correct for energy transfer between fluorophores
Image acquisition optimization:
Start acquisition with longer wavelengths to minimize photobleaching of FITC
Standardize exposure times across all comparable samples
Implement line averaging to improve signal-to-noise ratio
Use optical sectioning (confocal or deconvolution) to improve resolution of colocalization
Post-acquisition analysis strategies:
Apply spectral unmixing algorithms to separate overlapping signals
Use colocalization analysis software with appropriate coefficients (Pearson's, Manders')
Implement consistent thresholding methods for signal segregation
This methodological approach ensures accurate multiplexed detection of LPP alongside other proteins of interest in complex biological samples .
Site-specific conjugation technologies offer significant advantages over traditional random FITC conjugation methods for LPP antibodies:
Selenocysteine interface technology:
Incorporates selenocysteine (Sec), the 21st amino acid, at specific C-terminal positions
Exploits unique chemical reactivity of selenocysteine for selective conjugation
Creates precisely defined 1:1 stoichiometry between antibody and fluorophore
Maintains full antigen binding capability and effector functions
Performance advantages over traditional FITC conjugation:
Homogeneity: Traditional methods produce heterogeneous mixtures with variable drug-to-antibody ratios; site-specific methods generate uniform conjugates
Reproducibility: Batch-to-batch consistency is significantly improved with defined conjugation sites
Functional preservation: Site-specific methods avoid modification of antigen-binding regions, maintaining full binding capacity
Signal consistency: Uniform fluorophore-to-antibody ratio ensures consistent signal intensity per antibody molecule
Advanced conjugation approaches for LPP antibodies:
Dual C-terminal selenocysteine engineering allows higher fluorophore loading without compromising specificity
Enzymatic approaches using sortase A or transglutaminase for site-specific labeling
Click chemistry methods for bioorthogonal conjugation
Unnatural amino acid incorporation for expanded conjugation chemistry options
Comparative performance metrics:
| Parameter | Traditional FITC Conjugation | Site-Specific Conjugation |
|---|---|---|
| Stoichiometry | Variable (0-8 FITC/antibody) | Defined (typically 1-2/antibody) |
| Batch consistency | Moderate to low | High |
| Antigen binding | Often partially reduced | Fully maintained |
| Signal-to-noise ratio | Variable | Consistent and optimized |
| Photobleaching resistance | Standard | Can be improved with rational design |
Implementation considerations:
Initial investment in antibody engineering is higher but yields superior long-term performance
Advanced conjugation chemistry may require specialized expertise
Quality control methods must be adapted to verify site-specific modification
These site-specific conjugation approaches provide researchers with more consistent, reliable, and functionally preserved LPP antibody reagents for critical applications in both research and potential therapeutic development .
While FITC-conjugated antibodies are not typically the first choice for Western blotting due to fluorescence detection limitations in this format, researchers can adapt protocols to leverage LPP Antibody-FITC in this application with the following methodological considerations:
Sample preparation optimization:
Lyse cells in RIPA or NP-40 buffer supplemented with protease inhibitors
Include phosphatase inhibitors if phosphorylation status affects LPP detection
Determine optimal protein loading (typically 20-50 μg total protein)
Heat samples at 95°C for 5 minutes in Laemmli buffer with β-mercaptoethanol
Gel electrophoresis parameters:
Transfer considerations:
Optimize transfer conditions for LPP's molecular weight (typically 100V for 60-90 minutes)
Use PVDF membranes which provide better fluorescence signal than nitrocellulose
Verify transfer efficiency using reversible protein stains
Blocking and antibody incubation:
Block membranes with 3-5% BSA in TBS-T for 1 hour at room temperature
Incubate with LPP Antibody-FITC at optimized dilution (starting at 1:1000) overnight at 4°C
Protect from light during all incubation steps to prevent photobleaching
Wash extensively (5-6 times, 5-10 minutes each) with TBS-T
Detection system options:
Direct fluorescence detection: Use fluorescence imaging systems with appropriate excitation/emission settings for FITC
Indirect detection: Use anti-FITC antibodies conjugated with HRP followed by chemiluminescent detection
Dual verification: If signal is weak, follow with standard anti-LPP primary and appropriate secondary for confirmation
Imaging and quantification:
Use fluorescence scanners with 488 nm excitation capability
Implement exposure settings below saturation for accurate quantification
Include loading controls (GAPDH, β-actin) detected with spectrally distinct fluorophores
Use analysis software to normalize band intensity to loading controls
Troubleshooting considerations:
If direct fluorescence signal is weak, consider anti-FITC amplification or switch to conventional indirect detection
Minimize environmental light exposure during all steps
Optimize antibody concentration if background is high or specific signal is low
This adapted protocol allows researchers to utilize LPP Antibody-FITC in Western blotting applications while maximizing detection sensitivity and specificity .
LPP Antibody-FITC provides powerful capabilities for investigating LPP's role in cell adhesion dynamics through the following methodological approaches:
Live-cell imaging strategies:
Microinjection of LPP Antibody-FITC into living cells to track endogenous LPP
Combination with fluorescently tagged adhesion proteins (paxillin-mCherry, vinculin-mRFP)
Time-lapse microscopy to capture dynamic assembly/disassembly of adhesion complexes
FRAP (Fluorescence Recovery After Photobleaching) to measure LPP turnover rates at adhesion sites
Adhesion perturbation experiments:
Monitor LPP redistribution during cell adhesion to different ECM components (fibronectin, collagen, laminin)
Track LPP dynamics during force application using stretch chambers or micropatterned substrates
Analyze LPP localization following cytoskeletal disruption (cytochalasin D, nocodazole)
Quantify adhesion strength using centrifugal or fluidic detachment assays in LPP-manipulated cells
Advanced microscopy techniques:
Super-resolution microscopy (STORM, PALM) to visualize nanoscale organization of LPP within adhesion complexes
TIRF (Total Internal Reflection Fluorescence) microscopy to selectively image LPP at basal adhesion sites
FRET analysis using LPP Antibody-FITC and complementary fluorophore-labeled adhesion proteins to detect direct molecular interactions
Correlative light-electron microscopy to contextualize LPP localization with ultrastructural features
Mutation and domain analysis:
Compare localization patterns of wild-type vs. mutant LPP using domain-specific antibodies
Assess effects of LPP phosphorylation state on adhesion dynamics
Evaluate nucleus-cytoplasm shuttling using nuclear export/import inhibitors
Quantitative analysis approaches:
Measure adhesion complex assembly/disassembly rates in relation to LPP recruitment
Calculate spatial-temporal correlation between LPP intensity and adhesion maturation markers
Develop computational models predicting LPP contribution to adhesion mechanics
Functional correlates:
Monitor cell migration speed and directionality in relation to LPP dynamics
Analyze mechanical properties (stiffness, contractility) using traction force microscopy
Quantify signal transduction events downstream of LPP-containing adhesions
This integrated methodological framework enables comprehensive investigation of LPP's structural and signaling roles in cell adhesion dynamics, providing insights into its functions in normal physiology and disease contexts .
LPP Antibody-FITC offers valuable methodological approaches for evaluating LPP as a prognostic biomarker in cancer research:
These methodological approaches enable robust evaluation of LPP as a prognostic biomarker, potentially improving patient stratification and treatment selection, particularly for immunotherapy in gastric cancer and other malignancies .
Implementing LPP Antibody-FITC in high-throughput screening requires specific methodological considerations to ensure data quality, reproducibility, and scalability:
Assay miniaturization strategy:
Optimize for 96-, 384-, or 1536-well plate formats
Determine minimum cell density required for reliable LPP detection
Establish minimum antibody concentration that maintains signal-to-noise ratio
Develop automated liquid handling protocols for consistent reagent dispensing
Automated sample processing:
Implement robotic systems for cell seeding, fixation, permeabilization, and staining
Standardize fixation protocols to preserve LPP epitopes while allowing antibody penetration
Optimize washing steps to minimize well-to-well variability
Develop barcoding systems for sample tracking and quality control
Image acquisition parameters:
Configure automated microscopy with appropriate optical settings for FITC detection
Establish consistent exposure settings to enable cross-plate comparisons
Implement autofocus algorithms optimized for your specific cell types
Determine optimal sampling (fields per well) to balance throughput with statistical power
High-content analysis pipeline:
Develop segmentation algorithms for accurate cell identification
Extract multiparametric features (intensity, texture, morphology, subcellular distribution)
Implement machine learning approaches for phenotypic classification
Establish quality control metrics to flag and exclude problematic wells/fields
Validation controls and standards:
Include plate-specific positive and negative controls
Implement positional controls to detect edge effects
Use fluorescence calibration beads to normalize signal intensity between plates and days
Establish Z'-factor criteria for assay quality assessment
Data management and analysis:
Develop database structures to handle large image and feature datasets
Implement normalization methods to account for plate-to-plate variation
Establish statistical thresholds for hit identification
Create visualization tools for multidimensional data exploration
Specific applications with LPP Antibody-FITC:
Drug screening to identify compounds modulating LPP expression or localization
siRNA/CRISPR screens to identify genes affecting LPP function
Identifying compounds that might reverse high LPP expression in cancer samples
Screening for molecules that affect LPP's interaction with the immune microenvironment
These methodological considerations enable efficient implementation of LPP Antibody-FITC in high-throughput screening platforms, facilitating discovery of compounds or genetic factors that modulate LPP biology in normal physiology and disease contexts .
The development and application of LPP antibodies, particularly FITC-conjugated versions, continues to evolve with several promising future research directions:
Advanced conjugation technologies:
Expansion of selenocysteine interface technology for site-specific conjugation of LPP antibodies with improved fluorophores beyond FITC
Development of dual-conjugated antibodies combining FITC with complementary probes for multimodal imaging
Creation of photoactivatable LPP antibody conjugates for super-resolution microscopy applications
Clinical translation:
Mechanistic investigations:
Elucidation of LPP's role in mediating tumor-immune interactions using advanced antibody-based imaging
Investigation of LPP's function in cellular mechanotransduction using force-sensitive antibody conjugates
Exploration of LPP's involvement in other disease contexts beyond cancer
Technological innovations:
Integration with emerging spatial transcriptomics techniques for correlative protein-RNA analysis
Development of intrabody applications for live-cell tracking of endogenous LPP
Implementation in tissue clearing and 3D imaging protocols for volumetric analysis
Therapeutic applications:
Exploration of anti-LPP antibodies as potential therapeutic agents
Development of antibody-drug conjugates targeting LPP in appropriate disease contexts
Investigation of combination approaches targeting LPP alongside immune checkpoint inhibitors