4-1BB co-stimulation further enhances anti-PD-1-mediated reinvigoration of exhausted CD39+ CD8 T cells from primary and metastatic sites of epithelial ovarian cancers
Authors and Affiliations
Authors and Affiliations
Galam Leem1, Junsik Park2, Minwoo Jeon1, Eui-Soon Kim1, Sang Wun Kim2, Yong Jae Lee2, Seong Jin Choi1, Baekgyu Choi3, Seongyeol Park1, Young Seok Ju1, Inkyung Jung3, Sunghoon Kim2, Eui-Cheol Shin1, Jung Yun Lee2,* and Su-Hyung Park1,*
1Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
2Department of Obstetrics and Gynecology, Yonsei University College of Medicine, Seoul, Republic of Korea
3Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
*Correspondence to Dr Su-Hyung Park; Dr Jung Yun Lee;
GL and JP are joint first authors.
Responses to immunotherapy vary between different cancer types and sites. Here, we aimed to investigate features of exhaustion and activation in tumor-infiltrating CD8 T cells at both the primary and metastatic sites in epithelial ovarian cancer.
Tumor tissues and peripheral blood were obtained from 65 patients with ovarian cancer. From these samples, we isolated tumor-infiltrating lymphocytes (TILs) and peripheral blood mononuclear cells. These cells were used for immunophenotype using multicolor flow cytometry, gene expression profile using RNA sequencing and ex vivo functional restoration assays.
We found that CD39+ CD8 TILs were enriched with tumor-specific CD8 TILs, and that the activation status of these cells was determined by the differential programmed cell death protein 1 (PD-1) expression level. CD39+ CD8 TILs with high PD-1 expression (PD-1high) exhibited features of highly tumor-reactive and terminally exhausted phenotypes. Notably, PD-1high CD39+ CD8 TILs showed similar characteristics in terms of T-cell exhaustion and activation between the primary and metastatic sites. Among co-stimulatory receptors, 4-1BB was exclusively overexpressed in CD39+ CD8 TILs, especially on PD-1high cells, and 4-1BB-expressing cells displayed immunophenotypes indicating higher degrees of T-cell activation and proliferation, and less exhaustion, compared with cells not expressing 4-1BB. Importantly, 4-1BB agonistic antibodies further enhanced the anti-PD-1-mediated reinvigoration of exhausted CD8 TILs from both primary and metastatic sites.
Severely exhausted PD-1high CD39+ CD8 TILs displayed a distinctly heterogeneous exhaustion and activation status determined by differential 4-1BB expression levels, providing rationale and evidence for immunotherapies targeting co-stimulatory receptor 4-1BB in ovarian cancers.