TY - JOUR
T1 - The antitumor effects of vaccine-activated CD8+ T cells associate with weak TCR signaling and induction of stem-like memory T cells
AU - Wu, Sha
AU - Zhu, Wei
AU - Peng, Yibing
AU - Wang, Lan
AU - Hong, Yuan
AU - Huang, Lei
AU - Dong, Dayong
AU - Xie, Junping
AU - Merchen, Todd David
AU - Kruse, Edward James
AU - Guo, Zong Sheng
AU - Bartlett, David
AU - Fu, Ning
AU - He, Yukai
N1 - Publisher Copyright:
©2017 AACR.
PY - 2017/10
Y1 - 2017/10
N2 - To understand why vaccine-activated tumor-specific T cells often fail to generate antitumor effects, we studied two a-feto-protein–specific CD8+ T cells (Tet499 and Tet212) that had different antitumor effects. We found that Tet499 required high antigen doses for reactivation, but could survive persistent antigen stimulation and maintain their effector functions. In contrast, Tet212 had a low threshold of reactivation, but underwent exhaustion and apoptosis in the presence of persistent antigen. In vivo, Tet499 cells expanded more than Tet212 upon reencountering antigen and generated stronger antitumor effects. The different antigen responsiveness and antitumor effects of Tet212 and Tet499 cells correlated with their activation and differentiation states. Compared with Tet212, the population of Tet499 cells was less activated and contained more stem-like memory T cells (Tscm) that could undergo expansion in vivo. The TCR signaling strength on Tet499 was weaker than Tet212, correlating with more severe Tet499 TCR downregulation. Weak TCR signaling may halt T-cell differentiation at the Tscm stage during immune priming and also explains why Tet499 reactivation requires a high antigen dose. Weak TCR signaling of Tet499 cells in the effector stage will also protect them from exhaustion and apoptosis when they reencounter persistent antigen in tumor lesion, which generates antitumor effects. Further investigation of TCR downregulation and manipulation of TCR signaling strength may help design cancer vaccines to elicit a mix of tumor-specific CD8+ T cells, including Tscm, capable of surviving antigen restimulation to generate antitumor effects.
AB - To understand why vaccine-activated tumor-specific T cells often fail to generate antitumor effects, we studied two a-feto-protein–specific CD8+ T cells (Tet499 and Tet212) that had different antitumor effects. We found that Tet499 required high antigen doses for reactivation, but could survive persistent antigen stimulation and maintain their effector functions. In contrast, Tet212 had a low threshold of reactivation, but underwent exhaustion and apoptosis in the presence of persistent antigen. In vivo, Tet499 cells expanded more than Tet212 upon reencountering antigen and generated stronger antitumor effects. The different antigen responsiveness and antitumor effects of Tet212 and Tet499 cells correlated with their activation and differentiation states. Compared with Tet212, the population of Tet499 cells was less activated and contained more stem-like memory T cells (Tscm) that could undergo expansion in vivo. The TCR signaling strength on Tet499 was weaker than Tet212, correlating with more severe Tet499 TCR downregulation. Weak TCR signaling may halt T-cell differentiation at the Tscm stage during immune priming and also explains why Tet499 reactivation requires a high antigen dose. Weak TCR signaling of Tet499 cells in the effector stage will also protect them from exhaustion and apoptosis when they reencounter persistent antigen in tumor lesion, which generates antitumor effects. Further investigation of TCR downregulation and manipulation of TCR signaling strength may help design cancer vaccines to elicit a mix of tumor-specific CD8+ T cells, including Tscm, capable of surviving antigen restimulation to generate antitumor effects.
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U2 - 10.1158/2326-6066.CIR-17-0016
DO - 10.1158/2326-6066.CIR-17-0016
M3 - Article
C2 - 28851693
AN - SCOPUS:85030700008
SN - 2326-6066
VL - 5
SP - 908
EP - 919
JO - Cancer Immunology Research
JF - Cancer Immunology Research
IS - 10
ER -