PD-L1 rabbit monoclonal antibody [clone 28-8]: knockout validated and IHC optimized

PD-L1, a key biomarker for cancer therapeutic efficacy.

PD-L1 is a ligand that binds to PD-1 (programmed cell death-1) expressed on activated T cells to evade anti-tumor response. PD-L1 (also known as B7-H1, CD274) has emerged as an important target in cancer treatment. PD-L1 plays a role in inhibiting T cell activation and proliferation. Recent studies highlight PD-L1 as an important biomarker for immunotherapy outcomes. it is therefore vital to have reliable and reproducible tools to detect and measure PD-L1.  

Key specifications

Wild Type L2987 Cells

PD-L1 KO L2987 Cells

The panel aboves shows staining using anti-PD-L1 [28-8] RabMAb® antibody (ab205921) on wild type L2987 cells (Left) and PD-L1 knockout (KO) line of L2987 (right). PD-L1 gene was edited in L2987 human lung adenocarcinoma tumor cell line using TALEN constructs targeting exon 4 of human PD-L1. Complete KO was confirmed by deep sequencing.

B-CPAP Cells

ES-2 Cells

HCC70 Cells

COLO205 Cells

High expression

Med expression

Low expression

No expression

The panel above shows anti-PD-L1 [28-8] RabMAb® antibody (ab205921) staining on cancer cell lines that have varying levels of PD-L1 expression. B-CPAP has the highest expression and HCC70 has very low expression. There is no expression of PD-L1 reported in COLO205 cells.


1Phillips T, et al, 'Development of an Automated PD-L1 Immunohistochemistry (IHC) Assay for Non–Small Cell Lung Cancer' Immunotherapy' (2015) Applied Immunohistochemistry & Molecular Morphology, volume 23, issue 8, p541-549.

Alexa Fluor® is a registered trademark of Life Technologies. Alexa Fluor® dye conjugates contain(s) technology licensed to Abcam by Life Technologies.

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