T-Cell Activation/ Checkpoint Inhibitor Assay

Background: There are numerous checkpoint receptors; however, the most well-known is programmed cell death protein 1 (PD-1) and its ligand (PD-L1). Physiologically, checkpoint inhibitors mediate immune tolerance as a protective control measure during inflammation. In the case of PD-1/PD-L1, PD-1 is found on T and B cells, and is upregulated in response to stimulation. When these T and B cells come into contact with other cells expressing the matching ligand PD-L1, the T and B cells are tolerized and pro-inflammatory responses are suppressed. In cancer, tumor cells express an abundance of PD-L1 and effectively prevent the normal T-cell killing response. Treatment with inhibitors (usually monoclonal antibodies) that bind and block these surface receptors and ligands prevent immune tolerance and favors pro-inflammatory responses which help to overcome immune tolerance.

Principle: In this assay, stimulated lymphocytes are cultured for several days in the presence of a checkpoint inhibitor or other immunomodulatory article. Lymphocyte responses (proliferation, activation, cytokines, etc.) are measured and used to assess change caused by therapeutic intervention.


  1. Takeda, K., Yano, K., Yamada, K. & Kihara, A. Amlexanox enhances the antitumor effect of anti-PD-1 antibody. Biochem. Biophys. Res. Commun. 560, 1–6 (2021).
  2. Stecher, C. et al. PD-1 Blockade Promotes Emerging Checkpoint Inhibitors in Enhancing T Cell Responses to Allogeneic Dendritic Cells. Front. Immunol. 8, (2017).

 Related Assays:

  • Recall Antigen Assay
  • Antigen Specific T-cell activation Assay
  • T-cell Exhaustion Assay
  • T-Reg Suppression Assay
  • Tumor Cytotoxicity Assays