TY - JOUR
T1 - Radiotherapy and CTLA-4 blockade shape the tcr repertoire of tumor-infiltrating t cells
AU - Rudqvist, Nils Petter
AU - Pilones, Karsten A.
AU - Lhuillier, Claire
AU - Wennerberg, Erik
AU - Sidhom, John William
AU - Emerson, Ryan O.
AU - Robins, Harlan S.
AU - Schneck, Jonathan
AU - Formenti, Silvia C.
AU - Demaria, Sandra
N1 - Publisher Copyright:
© 2018 American Association for Cancer Research.
PY - 2018/2
Y1 - 2018/2
N2 - Immune checkpoint inhibitors activate T cells to reject tumors. Unique tumor mutations are key T-cell targets, but a comprehensive understanding of the nature of a successful antitumor T-cell response is lacking. To investigate the T-cell receptor (TCR) repertoire associated with treatment success versus failure, we used a well-characterized mouse carcinoma that is rejected by CD8 T cells in mice treated with radiotherapy (RT) and anti-CTLA-4 in combination, but not as monotherapy, and comprehensively analyzed tumor-infiltrating lymphocytes (TILs) by high-throughput sequencing of the TCRB CDR3 region. The combined treatment increased TIL density and CD8/CD4 ratio. Assessment of the frequency of T-cell clones indicated that anti-CTLA-4 resulted in fewer clones and a more oligoclonal repertoire compared with untreated tumors. In contrast, RT increased the CD8/CD4 ratio and broadened the TCR repertoire, and when used in combination with anti-CTLA-4, these selected T-cell clones proliferated. Hierarchical clustering of CDR3 sequences showed a treatment-specific clustering of TCRs that were shared by different mice. Abundant clonotypes were commonly shared between animals and yet treatment-specific. Analysis of amino-acid sequence similarities revealed a significant increase in the number and richness of dominant CDR3 motifs in tumors treated with RT \+ anti-CTLA-4 compared with control. The repertoire of TCRs reactive with a single tumor antigen recognized by CD8\+ T cells was heterogeneous but highly clonal, irrespective of treatment. Overall, data support a model whereby a diverse TCR repertoire is required to achieve tumor rejection and may underlie the synergy between RT and CTLA-4 blockade.
AB - Immune checkpoint inhibitors activate T cells to reject tumors. Unique tumor mutations are key T-cell targets, but a comprehensive understanding of the nature of a successful antitumor T-cell response is lacking. To investigate the T-cell receptor (TCR) repertoire associated with treatment success versus failure, we used a well-characterized mouse carcinoma that is rejected by CD8 T cells in mice treated with radiotherapy (RT) and anti-CTLA-4 in combination, but not as monotherapy, and comprehensively analyzed tumor-infiltrating lymphocytes (TILs) by high-throughput sequencing of the TCRB CDR3 region. The combined treatment increased TIL density and CD8/CD4 ratio. Assessment of the frequency of T-cell clones indicated that anti-CTLA-4 resulted in fewer clones and a more oligoclonal repertoire compared with untreated tumors. In contrast, RT increased the CD8/CD4 ratio and broadened the TCR repertoire, and when used in combination with anti-CTLA-4, these selected T-cell clones proliferated. Hierarchical clustering of CDR3 sequences showed a treatment-specific clustering of TCRs that were shared by different mice. Abundant clonotypes were commonly shared between animals and yet treatment-specific. Analysis of amino-acid sequence similarities revealed a significant increase in the number and richness of dominant CDR3 motifs in tumors treated with RT \+ anti-CTLA-4 compared with control. The repertoire of TCRs reactive with a single tumor antigen recognized by CD8\+ T cells was heterogeneous but highly clonal, irrespective of treatment. Overall, data support a model whereby a diverse TCR repertoire is required to achieve tumor rejection and may underlie the synergy between RT and CTLA-4 blockade.
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U2 - 10.1158/2326-6066.CIR-17-0134
DO - 10.1158/2326-6066.CIR-17-0134
M3 - Article
C2 - 29180535
AN - SCOPUS:85041910935
SN - 2326-6066
VL - 6
SP - 139
EP - 150
JO - Cancer Immunology Research
JF - Cancer Immunology Research
IS - 2
ER -