Recognition of human gastrointestinal cancer neoantigens by circulating PD-1+ lymphocytes
Alena Gros, … , James C. Yang, Steven A. Rosenberg
Alena Gros, … , James C. Yang, Steven A. Rosenberg
Published October 14, 2019
Citation Information: J Clin Invest. 2019;129(11):4992-5004. https://doi.org/10.1172/JCI127967.
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Research Article Immunology Oncology

Recognition of human gastrointestinal cancer neoantigens by circulating PD-1+ lymphocytes

Abstract

Tumor-resident lymphocytes can mount a response against neoantigens expressed in microsatellite-stable gastrointestinal (GI) cancers, and adoptive transfer of neoantigen-specific lymphocytes has demonstrated antitumor activity in selected patients. However, whether peripheral blood could be used as an alternative minimally invasive source to identify lymphocytes targeting neoantigens in patients with GI cancer with relatively low mutation burden is unclear. We used a personalized high-throughput screening strategy to investigate whether PD-1 expression in peripheral blood could be used to identify CD8+ or CD4+ lymphocytes recognizing neoantigens identified by whole-exome sequencing in 7 patients with GI cancer. We found that neoantigen-specific lymphocytes were preferentially enriched in the CD8+PD-1+/hi or CD4+PD-1+/hi subsets, but not in the corresponding bulk or PD-1– fractions. In 6 of 7 individuals analyzed we identified circulating CD8+ and CD4+ lymphocytes targeting 6 and 4 neoantigens, respectively. Moreover, neoantigen-reactive T cells and a T cell receptor (TCR) isolated from the CD8+PD-1+ subsets recognized autologous tumor, albeit at reduced levels, in 2 patients with available cell lines. These data demonstrate the existence of circulating T cells targeting neoantigens in GI cancer patients and provide an approach to generate enriched populations of personalized neoantigen-specific lymphocytes and isolate TCRs that could be exploited therapeutically to treat cancer.

Authors

Alena Gros, Eric Tran, Maria R. Parkhurst, Sadia Ilyas, Anna Pasetto, Eric M. Groh, Paul F. Robbins, Rami Yossef, Andrea Garcia-Garijo, Carlos A. Fajardo, Todd D. Prickett, Li Jia, Jared J. Gartner, Satyajit Ray, Lien Ngo, John R. Wunderllich, James C. Yang, Steven A. Rosenberg

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Figure 2

Detection of circulating CD4+ neoantigen-specific lymphocytes in a patient with gastroesophageal cancer (NCI-4078).

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Detection of circulating CD4+ neoantigen-specific lymphocytes in a patie...
(A) In vitro–expanded PBL subsets were cocultured with autologous DCs pulsed with DMSO or with the indicated PPs containing the putative mutations identified by WES. T cell reactivity was measured the next day by IFN-γ ELISPOT assay. (B) Reactivity of peripheral blood CD4+PD-1hi cells to DCs pulsed with an irrelevant peptide or peptides P1-7 and P2-15. Representative plots display the percentage of 4-1BB expression on live CD3+CD4+ lymphocytes. (C) P1-7– and P2-15–reactive cells isolated in B and expanded were cocultured with DCs pulsed with decreasing concentrations of TMPRSS4p.H233Y and PSMD2p.G644A WT and mutated 25-mers. Flow cytometric analysis of 4-1BB upregulation on CD3+CD4+ cells is plotted. (D and E) Reactivity of gene-engineered PBLs with dominant TMPRSS4p.H233Y- or PSMD2p.G644A-specific candidate TCR-α/β pairs from Table 1 to autologous DCs pulsed with WT and mutated TMPRSS4p.H233Y (D) and PSMD2p.G644A (E) 25-mers. Reactivity was measured by flow cytometric analysis of 4-1BB upregulation on CD8+mTCRB+ lymphocytes, and representative plots are shown. The individual neoantigens recognized and the amino acid position and change are noted. “>500” denotes greater than 500 spots per 2 × 104 cells. Experiments were performed without technical duplicates. Data from A–E are representative of at least 2 independent experiments.