Human PD-L1 OneStep ELISA Kit

Catalog Number: S0C3228 Reactivity: Hu Conjugation: Brand: Starter

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$160 USD

Size: 1x24T 1x48T 1x96T 5x96T 10x96T

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Product Details

Product Specification

Antigen	PD-L1
Immunogen	Recombinant Protein
Antibody Type	Recombinant mAb
Reactivity	Hu
Purification	Protein A
Stability & Storage	12 months from date of receipt / reconstitution, 2 to 8°C as supplied.

Kit

Precision	Intra-assay: 5.5%； Inter-assay: 6.9%
Sample type	Serum; EDTA Plasma, Citrate Plasma; Cell Culture Supernatant
Assay type	Sandwich (quantitative)
Sensitivity	2.95 pg/mL
Range	12.5 pg/mL – 800 pg/mL
Recovery	Serum: 105% EDTA Plasma: 103% Citrate plasma: 94% Cell Culture Supernatant: 120%
Assay time	60 minutes
Species reactivity	Hu

Background

Human PD-L1 (programmed death-ligand 1) is a 290-amino acid type I transmembrane glycoprotein encoded by the CD274 gene, also known as B7-H1 or CD274. It is a member of the B7 family of immune regulatory molecules and consists of a signal peptide (residues 1–18), an extracellular domain (residues 19–238) containing IgV-like and IgC-like subdomains, a transmembrane region (residues 239–259), and a short cytoplasmic domain of approximately 31 amino acids. The extracellular IgV domain serves as the primary binding interface for its receptor PD-1, mediating a large hydrophobic interaction surface that stabilizes the ligand-receptor complex. As a key immune checkpoint molecule, PD-L1 functions by binding to PD-1 on activated T cells, delivering inhibitory signals that suppress T cell proliferation and effector function, thereby contributing to immune tolerance and preventing excessive immune-mediated tissue damage. Unlike constitutively expressed surface markers, PD-L1 expression is highly inducible and upregulated in response to inflammatory cytokines such as interferon-γ and tumor necrosis factor-α, as well as under conditions of persistent antigenic stimulation in the tumor microenvironment. In oncology, PD-L1 expression in tumor tissues and immune cells has become an established biomarker for predicting the efficacy of immune checkpoint inhibitors, with higher expression levels generally correlating with greater clinical benefit from anti-PD-1/PD-L1 therapies. Researchers commonly assess PD-L1 expression by immunohistochemistry using standardized scoring systems such as the tumor proportion score or combined positive score to guide patient stratification in cancer immunotherapy. Because it can be reliably detected in formalin-fixed paraffin-embedded tumor specimens, PD-L1 serves as a practical and sensitive indicator for identifying patients likely to respond to checkpoint blockade. Thus, it plays a central role in both the mechanistic understanding of tumor immune evasion and the clinical evaluation of immunotherapeutic interventions in human cancer.

Picture

ELISA

Standard Curve
Example of Human PD-L1 BNP standard curve in Assay Diluent TF4. Plotted are the background-subtracted data.
This standard curve is provided for demonstration only.

Spike Recovery
The recovery of Human PD-L1 BNP was evaluated in activated samples spiked with concentrations spanning the entire assay range.

Dilution linearity
The concentration of Human PD-L1 in mice was measured and interpolated using the target standard curve, and the influence of sample dilution was corrected.
The bars on the left side of the figure represent the undiluted biological samples, and "undiluted" is defined as 50% dilution. The subsequent bars represent the two-fold consecutive dilutions of this reference sample. The average target concentration in human serum was measured to be 278.4 pg/mL.

Dilution linearity
The concentration of Human PD-L1 in mice was measured and interpolated using the target standard curve, and the influence of sample dilution was corrected.
The bars on the left side of the figure represent the undiluted biological samples, "undiluted" being defined as 50% dilution. The subsequent bars represent the two-fold consecutive dilutions of this reference sample. The average target concentration in the supernatant of PBMCs induced by 5 μg/mL PHA for 10 days was measured to be 144.98 pg/mL.

Spike-and-dilution Linearity
To evaluate assay linearity, three samples were spiked with high levels of Human PD-L1 BNP in different matrices and serially diluted with the corresponding Calibrator Diluent to fall within the assay's dynamic range.

Intra-Assay Precision (Precision within an assay)
Three samples of known concentration were tested fifteen times on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays).
Three samples of known concentration were tested in separate assays to assess inter-assay precision. Assays were performed with at least three lots of components.

Determination of Minimum Detectable Dose (MDD)
The MDD was determined using three independent lots of assay components. For each lot, 19 replicate measurements of the diluent (zero calibrator) were performed. The mean (AVERAGE) and standard deviation (STDEV) of the 19 replicates were calculated. The MDD for each lot was then calculated according to the following formula:
MDD = 2 × STDEV + AVERAGE

Cross-reactivity
The cross-reactivity between Mouse PD-L1 and Human PD-L1 was assessed by testing both proteins in the same assay system. Serial dilutions of each protein were measured, and the dose-response curves were compared. No significant cross-reactivity was observed when Mouse PD-L1 was tested in the Human PD-L1 BNP assay, as the signals remained within the background range of the assay.

HOOK Effect Threshold
The upper limit of the HOOK effect was established at 100× the highest calibrator concentration (equivalent to a 2-log10 increase). No HOOK effect was observed below this threshold, confirming that samples within this concentration range yield reliable quantitative results without signal depression.