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Journal of Immunology Research
Volume 2017, Article ID 7659462, 6 pages
https://doi.org/10.1155/2017/7659462
Research Article

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

1Biology Discipline, University of Minnesota, Morris, MN, USA
2Department of Immunology, Mayo Clinic, Rochester, MN, USA

Correspondence should be addressed to Rachel M. Gibbons Johnson; ude.nmu.sirrom@snhojmr

Received 7 August 2017; Revised 13 September 2017; Accepted 24 September 2017; Published 18 October 2017

Academic Editor: Guobing Chen

Copyright © 2017 Meagan R. Rollins and Rachel M. Gibbons Johnson. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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.