PLBL2 is a 76 kDa CHO-derived protein that co-purifies with therapeutic MAbs during downstream processing . It belongs to the phospholipase B-like family and contains two conserved peptide domains that remain associated under non-denaturing conditions . PLBL2 binds to the F(ab′)2 region of certain MAbs, leading to persistent contamination in final drug products .
PLBL2-specific antibodies are critical for monitoring impurity levels in biotherapeutics. Two ELISA formats have been validated:
Polyclonal Antibody-Based ELISA: Uses rabbit anti-PLBL2 antibodies for capture and horseradish peroxidase (HRP)-conjugated detection .
Monoclonal Antibody-Based ELISA: Employs mouse-derived anti-PLBL2 MAbs for higher specificity .
| Assay Parameter | Polyclonal ELISA | Monoclonal ELISA |
|---|---|---|
| Detection Limit | 0.3 ng/mg | <1 ng/mg |
| Dynamic Range | 1–10 ng/mL | 0.5–50 ng/mL |
| Cross-Reactivity | None with MAb 1 | None with MAb 1 |
| Application | Process monitoring | Final product release |
Rabbit polyclonal antisera detect PLBL2 down to ≥2 ng/lane, identifying both full-length protein and a clipped fragment (Figure 3 in ).
Recombinant human PLBD2 antibodies (e.g., ab213295) show a 42 kDa band in Western blots, suggesting isoform-specific cleavage .
PLBL2 levels in early MAb 2 batches reached 300 ng/mg, causing nonlinear dilution in HCP ELISAs due to antigen excess .
Process optimization (e.g., hydroxyapatite chromatography) reduced PLBL2 to <1 ng/mg .
In phase III trials for an asthma therapeutic (likely lebrikizumab), 90% of subjects developed anti-PLBL2 antibodies, though no safety correlations were observed .
Updated processes with reduced PLBL2 levels led to dose-dependent decreases in immune responses .
Binding Interaction: Surface plasmon resonance (SPR) confirmed PLBL2 binds the F(ab′)2 region of MAbs, not the Fc domain (Figure 7 in ).
Structural Stability: PLBL2’s two peptide domains dissociate only under denaturing conditions, complicating removal .
Antigen Excess: PLBL2 concentrations >10 ng/mL cause ELISA signal saturation, necessitating sample dilution .
Assay Variability: Commercial HCP ELISAs may lack sensitivity to PLBL2, risking undetected impurities .
PBL22 Antibody is a polyclonal antibody raised in rabbits against the Arabidopsis thaliana PBL22 protein. The antibody specifically recognizes the PBL22 protein, which is encoded by the Q9SFX0 Uniprot sequence. This antibody is designed for research applications targeting plant proteins, particularly in Arabidopsis thaliana (Mouse-ear cress) experimental systems .
PBL22 Antibody has been validated for several research applications, with ELISA and Western Blot (WB) being the primary validated methods. These applications ensure proper identification of the target antigen in experimental settings. The antibody is purified using antigen affinity methods, which enhances its specificity for the intended target .
For optimal preservation of antibody activity, PBL22 Antibody should be stored at -20°C or -80°C immediately upon receipt. Repeated freeze-thaw cycles should be avoided as they can compromise antibody performance. The antibody is typically supplied in a liquid form containing 50% glycerol and 0.01M PBS (pH 7.4) with 0.03% Proclin 300 as a preservative, which helps maintain stability during storage .
Researchers should employ multiple complementary approaches to validate PBL22 Antibody specificity:
Positive and negative controls: Include known positive samples expressing PBL22 and negative controls where the protein is absent.
Knockout/knockdown validation: When possible, use genetic approaches where PBL22 expression is eliminated or reduced to confirm antibody specificity .
Multiple detection methods: Validate findings using at least two independent detection methods (e.g., Western blot and immunofluorescence) .
Peptide competition assay: Pre-incubate the antibody with purified antigen (recombinant PBL22) to block specific binding sites before application to samples .
These validation steps are crucial since antibody specificity issues have led to significant errors in scientific literature, as demonstrated in studies of other proteins like C9ORF72 .
A robust experimental design with PBL22 Antibody should include:
| Control Type | Purpose | Implementation |
|---|---|---|
| Positive Control | Confirms antibody functionality | Known PBL22-expressing Arabidopsis thaliana tissue/cells |
| Negative Control | Assesses non-specific binding | Samples lacking PBL22 expression or knockout models |
| Isotype Control | Evaluates background from antibody class | Matched rabbit IgG at equivalent concentration |
| Secondary Antibody Control | Detects non-specific binding of secondary reagent | Omit primary antibody, include only secondary detection |
| Peptide Competition | Confirms epitope specificity | Pre-incubate antibody with immunogen peptide |
These controls help distinguish true signals from technical artifacts, which is particularly important when working with polyclonal antibodies that may contain antibodies recognizing multiple epitopes .
While specific dilution recommendations for PBL22 Antibody should be determined empirically for each experimental system, general guidelines based on similar antibodies suggest:
For ELISA: Initial testing at 1:1000 dilution with optimization between 1:500-1:5000
For Western Blot: Starting dilution of 1:1000 with titration between 1:500-1:2000
For Immunohistochemistry: Begin with 1:100 and adjust between 1:50-1:200
Each new lot of antibody should be titrated to determine optimal working concentrations as variations can occur between manufacturing batches .
When encountering non-specific binding with PBL22 Antibody, researchers can implement several optimization strategies:
Increase blocking efficiency: Use 5% BSA or 5% milk in TBS-T for Western blots or increase blocking time.
Optimize antibody concentration: Titrate the antibody to find the concentration that maximizes specific signal while minimizing background.
Modify washing procedures: Increase the number and duration of wash steps to remove unbound antibody.
Add protein competitors: Include 1-5% normal serum from the species of the secondary antibody in the primary antibody diluent.
Use alternative buffers: Test different buffer compositions that may reduce non-specific interactions between the antibody and sample components .
Non-specific binding is particularly problematic with polyclonal antibodies, which contain a heterogeneous mixture of immunoglobulins that may recognize multiple epitopes with varying affinities .
Several factors can impact experimental reproducibility when working with PBL22 Antibody:
Sample preparation methods: Variations in fixation, permeabilization, or protein extraction protocols can affect epitope accessibility.
Antibody storage conditions: Improper storage leading to antibody degradation or aggregation.
Lot-to-lot variability: Polyclonal antibodies may show batch-dependent variations in specificity and sensitivity.
Experimental conditions: Changes in incubation time, temperature, or buffer composition between experiments.
Technical execution: Inconsistencies in washing steps, detection methods, or imaging parameters.
Researchers should standardize protocols and maintain detailed records of antibody lots and experimental conditions to enhance reproducibility .
To extend the use of PBL22 Antibody to other plant species, researchers should:
Perform sequence homology analysis: Compare the immunogen sequence across potential target species to identify conservation of the epitope region.
Conduct cross-reactivity tests: Systematically test the antibody against protein extracts from multiple species using Western blot.
Validate with recombinant proteins: Express the target protein from different species and test antibody recognition.
Use genetic controls: When available, employ knockout or knockdown models from alternative species to confirm specificity.
Implement epitope mapping: Identify the specific regions recognized by the antibody to predict cross-reactivity with homologs.
Cross-species validation is critical as antibody reactivity should be established on a species-by-species basis, even for highly conserved proteins .
For validating PBL22 Antibody in ChIP applications, researchers should implement a comprehensive approach:
Epitope accessibility assessment: Determine if the antibody recognizes the native, chromatin-associated form of PBL22.
ChIP-qPCR validation: Confirm enrichment at known binding sites and absence of signal at negative control regions.
Input normalization: Compare ChIP signals to input controls to account for chromatin preparation biases.
Genetic validation: Use PBL22 knockout or knockdown samples as negative controls.
Reproducibility testing: Demonstrate consistent enrichment patterns across biological replicates.
Complementary methods: Validate key findings with orthogonal approaches like DNA affinity purification or EMSA.
ChIP validation is particularly important as antibodies that perform well in other applications may fail in ChIP due to epitope masking or formaldehyde-induced modifications to the antigen .
Developing multiplex experiments with PBL22 Antibody requires careful consideration of several factors:
Antibody compatibility: Ensure primary antibodies originate from different host species to prevent cross-reactivity with secondary detection reagents.
Spectral separation: When using fluorescent detection, select fluorophores with minimal spectral overlap to avoid bleed-through between channels.
Sequential detection: For antibodies from the same species, employ sequential staining with complete blocking between steps.
Signal amplification balance: Adjust detection sensitivity for each target to achieve comparable signal-to-noise ratios.
Optimization of multiplex conditions: Develop a unified protocol that preserves epitope recognition for all targets simultaneously.
Multiplexing enables the study of protein co-localization and complex interactions, but requires rigorous validation to ensure that each antibody maintains specificity and sensitivity in the multiplex setting .
When faced with discrepancies between PBL22 Antibody results and other experimental approaches:
Systematic validation: Re-evaluate antibody specificity using knockout controls and peptide competition assays.
Method-specific considerations: Recognize that different detection methods (e.g., Western blot vs. immunofluorescence) assess distinct aspects of protein biology and may yield apparently contradictory results.
Independent antibody validation: Test multiple antibodies targeting different epitopes of the same protein.
Integrated data analysis: Consider all available evidence, weighing the strengths and limitations of each approach.
Biological variability assessment: Determine if discrepancies reflect true biological variability rather than technical artifacts.
The scientific literature contains numerous examples where reliance on inadequately validated antibodies led to contradictory findings and misinterpretations, as demonstrated in studies of proteins like C9ORF72 .
Robust statistical analysis of PBL22 Antibody data should include:
Appropriate replication: Minimum of three biological replicates to capture natural variation.
Quantification methods: Use digital image analysis with defined intensity thresholds for consistent signal measurement.
Normalization strategies: Normalize to loading controls or reference proteins to account for technical variation.
Statistical tests: Apply appropriate parametric or non-parametric tests based on data distribution.
Multiple testing correction: When analyzing multiple samples or conditions, correct for increased likelihood of false positives.
Effect size reporting: Include measures of effect magnitude (e.g., fold change) alongside significance values.
Quantitative analysis enhances reproducibility and supports more nuanced interpretation of experimental findings beyond binary presence/absence assessments .
Incorporating PBL22 Antibody into single-cell technologies requires additional optimization considerations:
Conjugation chemistry: Direct labeling with fluorophores or barcodes compatible with single-cell platforms.
Validation at single-cell resolution: Confirm specificity using spike-in controls and correlation with mRNA expression.
Signal calibration: Develop standard curves to enable quantitative protein measurement.
Multiplexing capacity: Evaluate compatibility with antibody panels used in CyTOF or CITE-seq approaches.
Protocol adaptation: Modify fixation and permeabilization procedures to maintain both cellular integrity and epitope accessibility.
Single-cell protein analysis provides crucial insights into cellular heterogeneity that complement bulk measurements, but requires extensive validation to ensure accurate interpretation .
When integrating PBL22 Antibody data with computational image analysis:
Signal standardization: Apply consistent image acquisition settings and normalization approaches.
Feature extraction: Define relevant cellular features (e.g., subcellular localization patterns, intensity distributions).
Training data quality: Ensure training datasets include appropriate positive and negative controls.
Model validation: Implement cross-validation strategies to assess model robustness.
Biological validation: Confirm computational predictions with orthogonal biological assays.
Threshold optimization: Establish signal thresholds that distinguish specific binding from background.
Machine learning approaches can extract complex patterns from antibody-based imaging data but require careful validation to avoid propagating technical artifacts or biases .