PRAMEF10 (PRAME family member 10) is a protein encoded by the PRAMEF10 gene (UniProt: O60809) and belongs to the PRAME (Preferentially Expressed Antigen in Melanoma) family, which is implicated in cancer biology and immune regulation . The FITC-conjugated antibody enables visualization of this protein in cellular assays.
The antibody is generated using either:
Recombinant protein: Full-length human PRAMEF10 (1-261 amino acids) .
Synthetic peptide: A 45-amino acid sequence (DLLRHTGGLSKLGLELYPAPLESLDYKGHVNWEILTPIRAELMRTLREVR) from the middle region of PRAMEF10 .
Both immunogens ensure specificity, though recombinant protein-based antibodies may offer broader epitope recognition.
Immunofluorescence (IF): Localizes PRAMEF10 in fixed cells or tissues using FITC’s green fluorescence .
Flow Cytometry: Detects surface or intracellular PRAMEF10 in live or fixed cells .
Dilution: User-dependent; preliminary testing at 0.2–1 µg/mL is recommended .
Quenching Risk: High FITC-conjugate concentrations (>0.5 µg/test) may reduce fluorescence intensity .
Advantages: Stable fluorescence, easy protein conjugation, and compatibility with blue (488 nm) lasers .
Limitations: Susceptible to photobleaching; requires shielded storage.
No cross-reactivity with non-human species has been reported .
PRAMEF10’s role remains under investigation, but its association with the PRAME family suggests potential involvement in:
Cancer immune evasion mechanisms.
Germline development and epigenetic regulation.
The FITC-conjugated antibody facilitates high-resolution studies of PRAMEF10’s spatial expression, aiding hypotheses about its biological functions .
Validation requires a multi-step approach:
Knockdown/knockout controls: Use siRNA or CRISPR-Cas9 to reduce PRAMEF10 expression in cell lines, followed by flow cytometry or immunofluorescence to confirm signal reduction .
Competitive blocking: Pre-incubate the antibody with excess recombinant PRAMEF10 protein; a ≥80% reduction in fluorescence intensity indicates specificity .
Cross-reactivity profiling: Test against protein arrays containing homologous family members (e.g., PRAMEF1-PRAMEF12) to rule out off-target binding .
| Parameter | Acceptable Threshold | Method |
|---|---|---|
| Signal-to-noise ratio | ≥5:1 | Flow cytometry (compared to isotype control) |
| Blocking efficiency | ≥80% reduction | Competitive ELISA |
| Batch consistency | CV <15% | Inter-assay comparison (n=3 replicates) |
Critical parameters include:
Fixation: Paraformaldehyde (2–4%) preserves epitopes better than methanol-based methods, which may denature PRAMEF10’s tertiary structure .
Permeabilization: Required for intracellular targets; 0.1% Triton X-100 for 10 min balances membrane integrity and antibody access .
Titration: Conduct checkerboard titrations (1:50–1:500) using positive control cells (e.g., MCF7 breast cancer line) to identify the signal-to-noise plateau .
Implement these quality controls:
Fluorophore-to-protein (F/P) ratio: Measure absorbance at 280 nm (protein) and 494 nm (FITC). Ideal F/P = 3–6 to balance brightness and steric hindrance .
Size-exclusion chromatography: Verify absence of unconjugated FITC or antibody aggregates, which cause non-specific binding .
Functional testing: Compare staining intensity between batches using standardized control cells, requiring ≤20% deviation in median fluorescence intensity (MFI) .
Discrepancies often arise from:
Epitope accessibility: IHC requires antigen retrieval (e.g., citrate buffer at pH 6.0), whereas flow cytometry uses intact cells. Validate with dual IHC/flow-validated cell pellets .
Temporal expression dynamics: PRAMEF10 shows cell cycle-dependent expression (peaking in S phase). Synchronize cell cycles or normalize data to proliferation markers (Ki-67) .
Post-translational modifications: Phosphorylation at Ser-15 modulates antibody binding. Treat lysates with λ-phosphatase to assess modification-dependent detection .
A sequential workflow is recommended:
Surface staining: Use PRAMEF10-FITC at 1:100 dilution in PBS/0.5% BSA for 30 min at 4°C.
Cell hashing: Label subsets with oligonucleotide-conjugated CD298 antibodies to multiplex samples .
Post-sequencing alignment: Map FITC+ cells to PRAMEF10 transcript clusters using tools like CITE-seq. Expect 70–85% concordance due to post-transcriptional regulation .
Compensation strategies include:
Pre-acquired spillover matrices: Collect single-stain controls for all fluorophores (e.g., FITC, PE, APC) using identical instrument settings .
Algorithmic correction: Apply linear unmixing (FlowJo v10.8) or machine learning-based tools (CyTOF Autoencoder) for datasets >15 parameters .
Validation: Confirm compensation accuracy by analyzing cells expressing mutually exclusive markers (e.g., CD3+CD19− vs. CD3−CD19+) .
Extended fixation introduces two challenges:
Epitope masking: Reverse with 30-min antigen retrieval in Tris-EDTA (pH 9.0) at 95°C .
Autofluorescence: Quench with 0.3% Sudan Black B in 70% ethanol for 10 min, reducing background by 60–70% .
Quantitative normalization: Include an internal reference standard (e.g., tonsil tissue) in each batch to calibrate inter-experimental variability .
Adapt the following steps from oncogenic microvesicle studies :
Isolation: Ultracentrifugation at 100,000×g for 90 min with a 30% sucrose cushion to exclude apoptotic bodies.
Capture: Anti-CD63 magnetic beads enrich exosome populations; validate purity via TEM and CD81 ELISA .
Staining: Incubate vesicles with PRAMEF10-FITC (1:50) in 0.1 µm-filtered PBS for 2 hr at 37°C.
Analysis: Use nanoFACS (Apogee A60) with 0.22 µm nozzle; gate on 100–300 nm particles via side scatter .
Implement reference-based calibration:
Standard curve: Stain a cell pellet series (0–100% PRAMEF10+ cells) to establish a linear regression model (R² >0.95) .
Pixel intensity normalization: Use HALO® software to normalize FITC signals to DAPI intensity within nuclear-adjacent regions .
Cross-platform alignment: Compare results with mass spectrometry (PRM assay for PRAMEF10 peptides) to correct for antibody affinity biases .
Deploy a tripartite approach:
CRISPR interference: Use dCas9-KRAB to repress PRAMEF10 transcription; protein should decrease proportionally .
Proximity ligation assay (PLA): Confirm spatial co-localization with known interactors (e.g., BMI1) using Duolink® reagents .
Western blot correlation: Run parallel SDS-PAGE under non-reducing conditions; bands at ~35 kDa (monomer) and ~70 kDa (dimer) validate antibody specificity .