Basic Research - Cancer(구연) Oral Session 3 / Basic Research - Cancer (Ⅱ) (O-024) Rm.201 10월 30일(수) 14:00-15:00 신세포암에 침윤한 종양 특이 CD8 T 세포 중에서 CD39를 발현하는 CD8 T 세포의 표현형적 특성 성균관대학교 의과대학 비뇨기과학교실, ¹카이스트 의과학대학원 면역감염질환연구실, ²연세대학교 의과대학 산부인과학 교실, ³카이스트 의과학대학원 중개면역 및 백신연구실 유현수, 이용준¹, 강민용, 성현환 전황균, 정병창, 전성수, 이현무, 박준식², 박수형³, 신의철¹, 서성일 Recent studies have spotlighted CD39 expression on tumor-infiltrating CD8+ T cells as an exhaustion marker (Cancer Research 2018, 1:78) and tumor antigen reactivity (Nature Communications 2018, 9:1). In the present study, we examined characteristics of CD39+CD8+ T cells among tumor-infiltrating lymphocytes (TILs) obtained from renal cell carcinoma, to gain better understanding of CD39 expression on CD8+ T cells. To identify tumor antigen-specific CD8+ T cells, we used 4 HLA-A*A201 multimers specific for tumor associated antigens, including MAGE A1, NY-ESO-1, and Melan A. CD39 expression of tumor antigen-specific CD8+ T cells was significantly higher in TILs than in peripheral blood lymphocytes. However, all of tumor-infiltrating tumor antigen-specific CD8+ T cells did not express CD39. As known previously (Nature 2018, 557:7706), tumor-infiltrating bystander CD8+ T cells, specific to viral epitopes, lack CD39 expression. Among tumor-infiltrating tumor antigen-specific CD8+ T cells, CD39+CD8+ T cells exhibited more severely exhausted features than CD39-CD8+ T cells. For example, the percentage of multiple immune checkpoint receptors-expressing cells was significantly higher in CD39+CD8+ T cells compared to CD39-CD8+ T cells. Moreover, higher proportion of T-betlow/Eomeshigh cells and and lower expression of CD127 were observed in CD39+CD8+ T cells. In addition, CD39+CD8+ T cells expressed higher levels of tissue residency markers, such as CD103 and CD69. In conclusion, CD39+CD8+ T cells exhibit distinct phenotypes that represent severe exhaustion and terminal differentiation among tumor-infiltrating tumor-antigen-specific CD8+ T cells in renal cell carcinoma. keywords : CD39+CD8+ T cells, tumor-antigen-specific CD8+ T cells , renal cell carcinoma