| First Author | Martínez-Usatorre A | Year | 2018 |
| Journal | J Immunol | Volume | 201 |
| Issue | 2 | Pages | 792-803 |
| PubMed ID | 29875150 | Mgi Jnum | J:264067 |
| Mgi Id | MGI:6192237 | Doi | 10.4049/jimmunol.1701644 |
| Citation | Martinez-Usatorre A, et al. (2018) PD-1 Blockade Unleashes Effector Potential of Both High- and Low-Affinity Tumor-Infiltrating T Cells. J Immunol 201(2):792-803 |
| abstractText | Antitumor T cell responses involve CD8(+) T cells with high affinity for mutated self-antigen and low affinity for nonmutated tumor-associated Ag. Because of the highly individual nature of nonsynonymous somatic mutations in tumors, however, immunotherapy relies often on an effective engagement of low-affinity T cells. In this study, we studied the role of T cell affinity during peripheral priming with single-peptide vaccines and during the effector phase in the tumor. To that end, we compared the antitumor responses after OVA257-264 (N4) peptide vaccination of CD8(+) T cells carrying TCRs with high (OT-1) and low (OT-3) avidity for the N4 peptide in B16.N4 tumor-bearing C57BL/6 mice. Additionally, we assessed the response of OT-1 cells to either high-affinity (B16.N4) or low-affinity (B16.T4) Ag-expressing tumors after high-affinity (N4) or low-affinity (T4) peptide vaccination. We noticed that although low-affinity tumor-specific T cells expand less than high-affinity T cells, they express lower levels of inhibitory receptors and produce more cytokines. Interestingly, tumor-infiltrating CD8(+) T cells show similar in vivo re-expansion capacity to their counterparts in secondary lymphoid organs when transferred to tumor-free hosts, suggesting that T cells in tumors may be rekindled upon relief of tumor immunosuppression. Moreover, our results show that alphaPD-1 treatment enhances tumor control of high- and low-affinity ligand-expressing tumors, suggesting that combination of high-affinity peripheral priming by altered peptide ligands and checkpoint blockade may enable tumor control upon low-affinity Ag recognition in the tumor. |
