CD80 Expressed by CD8+ T Cells Contributes to PD-L1-Induced Apoptosis of Activated CD8+ T Cells

• Published in: Journal of immunology research Vol. 2017; no. 2017; pp. 1 - 6
• Main Authors: Rollins, Meagan R., Gibbons Johnson, Rachel M.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2017; Hindawi; Hindawi Limited; Wiley
• Subjects: Antitumor activity; Apoptosis; Cancer; CD3 antigen; CD8 antigen; CD80 antigen; Cell surface; Cytokines; Fc receptors; Immune checkpoint; Immunology; Laboratory animals; Ligands; Lymphocytes; Lymphocytes T; Melanoma; Metabolism; Metastasis; PD-1 protein; PD-L1 protein; Proteins; Riella; Tumor cells; United States > US
• ISSN: 2314-8861; 2314-7156
• DOI: 10.1155/2017/7659462

Tumor cells are capable of limiting antitumor CD8+ T cell responses through their cell surface expression of PD-L1. In addition to PD-1 expressed by CD8+ T cells, PD-L1 also binds to CD80 expressed by CD8+ T cells. The influence of the PD-L1/CD80 interaction on CD8+ T cell function has not been fully characterized, so we sought to investigate the impact of the PD-L1/CD80 interaction on PD-L1-induced apoptosis of activated CD8+ T cells. We found that CD8+ T cells that lacked CD80 expression got activated to the same extent as wild-type CD8+ T cells, but when cultured with anti-CD3 and PD-L1/Fc protein, activated CD8+ T cells that lacked CD80 expression survived better than activated wild-type CD8+ T cells. These findings indicate that PD-L1 induces apoptosis in activated CD8+ T cells in part by signaling through CD80. Thus, in the design and implementation of checkpoint blockade therapies that target PD-L1, it is essential that both binding partners for PD-L1, PD-1, and CD80 are considered.