Established T cell dysfunction is a barrier to antitumor responses, and checkpoint blockade presumably reverses this. Many patients fail to respond to treatment and/or develop autoimmune adverse events. The underlying reason for T cell responsiveness remains elusive. Here, we show that susceptibility to checkpoint blockade is dependent on the activation status of T cells. Newly activated self-specific CD8 T cells respond to checkpoint blockade and cause autoimmunity, which is mitigated by inhibiting the mechanistic target of rapamycin. However, once tolerance is established, self-specific CD8 T cells display a gene signature comparable to tumor-specific CD8 T cells in a fixed state of dysfunction. Tolerant self-specific CD8 T cells do not respond to single or combinatorial dosing of anti-CTLA4, anti–PD-L1, anti–PD-1, anti–LAG-3, and/or anti–TIM-3. Despite this, T cell responsiveness can be induced by vaccination with cognate antigen, which alters the previously fixed transcriptional signature and increases antigen-sensing machinery. Antigenic reeducation of tolerant T cells synergizes with checkpoint blockade to generate functional CD8 T cells, which eliminate tumors without concomitant autoimmunity and are transcriptionally distinct from classic effector T cells. These data demonstrate that responses to checkpoint blockade are dependent on the activation state of a T cell and show that checkpoint blockade-insensitive CD8 T cells can be induced to respond to checkpoint blockade with robust antigenic stimulation to participate in tumor control.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Feb 12 2019|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. We thank Rachel Davis for expert technical assistance. This work was supported by the NIH Grant DP2OD006472 (to V.V.), the Randy Shaver Cancer Research Fund (V.V.), and the NIH Grant T32AI007313 (to C.E.N. and E.A.T.).
© 2019 National Academy of Sciences. All Rights Reserved.
- CD8 T cells