PD-L1 ELISA Kit (Human)

Cosmo Bio LTD

Catalog No: HAK-HELPDL1-1

This kit uses a one-step sandwich assay with a high-performance antibody against PD-L1, an immune checkpoint-related molecule, to quantify human PD-L1 in samples with high sensitivity.

Background

What is PD-L1?

Cancer cells express PD-L1 (programmed cell death ligand-1) on their surface, which is a receptor for the PD-1 receptor expressed on the surface of activated T cells, and suppress T cell activity through PD-1/PD-L1 binding, thereby evading immune surveillance1 ^{), 2)} . In recent years, these immune surveillance mechanisms have been applied to cancer treatment, and anti-PD-1 and anti-PD-L1 antibodies have been developed to enhance T cell activation by inhibiting this binding, and their clinical efficacy and safety have been confirmed in various solid cancers3 ^{), 4)} .
However, although resistance to treatment after the initial effect has been observed in many cases, the mechanism of resistance to anti-PD-L1 antibodies remains largely unknown.
Recently, two unique secreted PD-L1 splicing variants lacking the transmembrane domain have been identified in patients with anti-PD-L1-resistant NSCLC5 ⁾ .
It has been suggested that the secreted PD-L1 splicing variant induces resistance to PD-L1 inhibitors by acting as a decoy, and the levels of soluble PD-L1 in plasma (exosome-free) or pleural fluid in patients with the secreted PD-L1 splicing variant were higher than those in healthy donors or patients without the secreted PD-L1 variant.5 ⁾ Furthermore, it has been suggested that the blood concentration of soluble
PD-L1 may predict the clinicopathological characteristics, treatment response, and survival outcomes of cancer ^patients.6 )

Features

• Highly sensitive detection of human PD-L1 using the 1-Step ELISA method (detection sensitivity: 1 pg/mL ^* )
• No special equipment is required; measurements can be made with a regular plate reader.
  *Calculated from the standard deviation of blank absorbance and the slope of the calibration curve7 ⁾

Kit Components

Contents	capacity	quantity
Anti-PD-L1 antibody immobilized plate	96 well (8-well x 12 strips)	1 sheet
Standard PD-L1	100 µL	1pc ^*
Assay Buffer	15 mL	1 bottle
Washing buffer (10x)	15 mL	1 bottle
HRP-labeled anti-PD-L1 antibody (250×)	20 µL	1 bottle
Substrate solution	12 mL	1 bottle
Stop solution ( 2N H2SO4 )	6 mL	1 bottle
Plate seal	-	1 sheet

*; n=2, calibration curve 3 times

Specification

Cross-reactivity	Sample Type	Measurement range	sensitivity
Human	Serum, Plasma, Cell culture supernatant	12.5–800 pg/mL	1 pg/mL

Example data

Figure 1. Standard curve

Figure 2. Cell culture supernatant
(Time course of PD-L1 levels in the culture supernatant of PD-L1-overexpressing HEK293 cells)

 

Sample	Recovery rate (%)
	Average	range
serum	94%	92% - 99%
plasma	91%	88% - 93%

Spike recovery (serum, plasma)