The BioDeviceLab PD-L1 ELISA Kit is a high-performance sandwich enzyme-linked immunosorbent assay developed for the quantitative determination of soluble PD-L1 (sPD-L1) in biological samples. PD-L1 is a key immune checkpoint ligand expressed by tumor cells, antigen-presenting cells, and stromal cells and plays a central role in immune suppression through interaction with PD-1 on T cells. Dysregulation of the PD-1/PD-L1 axis is a hallmark of tumor immune evasion and is a major therapeutic target in cancer immunotherapy.
Circulating levels of soluble PD-L1 are increasingly investigated as biomarkers for disease prognosis, immune suppression, therapeutic response, and resistance to immune checkpoint inhibitors. This assay combines high analytical sensitivity, robust reproducibility, and a wide dynamic detection range, enabling accurate PD-L1 quantification across clinically and biologically relevant concentrations. The kit is suitable for routine laboratory analysis as well as advanced biodevice validation and calibration workflows.
For Research Use Only (RUO).
Intended Use
This kit is intended for the quantitative determination of soluble PD-L1 in:
• Serum
• Plasma
• Cell culture supernatants
Applications include immuno-oncology research, immune checkpoint signaling studies, immunotherapy response and resistance analysis, organ-on-chip immune–tumor models, and biodevice validation and benchmarking.
Assay Principle
This assay employs a sandwich ELISA format:
• Soluble PD-L1 present in the sample binds to capture antibodies immobilized on a 96-well microplate.
• A biotinylated detection antibody specific to PD-L1 binds to the captured protein.
• An enzyme conjugate is added, followed by a chromogenic substrate (TMB).
• The enzymatic reaction generates a color signal measured at 450 nm.
• Absorbance is directly proportional to the PD-L1 concentration in the sample.
Calibration Curve
• A calibration curve is generated using PD-L1 standards with known concentrations.
• Mean absorbance values are plotted against PD-L1 concentration on a semi-logarithmic scale.
• A four-parameter logistic (4PL) regression model is recommended for curve fitting.
• Sample concentrations are determined by interpolation from the standard curve.
• A new calibration curve should be generated for each assay run.
Analytical Performance
Dynamic detection range: 5 – 1,500 pg/mL
Limit of detection (LOD): ≤ 3 pg/mL
Intra-assay CV: < 10%
Inter-assay CV: < 12%
Selectivity & Specificity
The assay demonstrates high specificity for human PD-L1 with minimal cross-reactivity to related immune checkpoint proteins. Representative cross-reactivity levels:
• PD-L1: 100%
• PD-1, PD-L2, CTLA-4: < 1%
This specificity ensures reliable PD-L1 quantification in complex biological matrices.
Kit Components
Each kit contains sufficient reagents for up to 96 determinations:
• Antibody-coated 96-well microplate
• PD-L1 standards (lyophilized, multiple concentrations)
• Biotinylated detection antibody
• Enzyme conjugate
• Assay buffer
• Wash buffer (10×)
• TMB substrate
• Stop solution
• Detailed assay protocol
Required Materials (Not Provided)
• Microplate reader capable of measuring absorbance at 450 nm
• Adjustable micropipettes and disposable tips
• Plate washer or manual washing equipment
• Plate shaker (recommended)
• Deionized or distilled water
Sample Collection & Handling
• Collect samples using standard laboratory procedures.
• Avoid repeated freeze–thaw cycles.
• Samples exceeding the highest standard should be diluted using assay buffer.
• Hemolyzed or lipemic samples may affect assay accuracy.
Quality Control
• Standards and controls should be included in each assay run.
• Duplicate measurements are recommended.
• Acceptance criteria should be established by the user according to the intended application.
BioDeviceLab applies quality-controlled reagent preparation and batch-to-batch consistency practices to support reproducibility and scalability for biodevice development.
Storage & Stability
• Store all components at 2–8 °C.
• Do not freeze reagents unless explicitly stated.
• Unopened kits are stable until the stated expiration date.
• Opened reagents should be handled according to protocol recommendations.
Limitations
• For research use only.
• Not intended for diagnostic or therapeutic procedures.
• Results should be interpreted within the context of experimental design and sample matrix.
Applications
• Immuno-oncology and immune checkpoint research
• Cancer immunotherapy response and resistance studies
• Immune suppression and tumor microenvironment profiling
• Organ-on-chip immune–tumor models
• Biodevice calibration and benchmarking
Calibration Curve
