Natural TCRs targeting KRASG12V display fine specificity and sensitivity to human solid tumors
Adham S. Bear, … , Gerald P. Linette, Beatriz M. Carreno
Adham S. Bear, … , Gerald P. Linette, Beatriz M. Carreno
Published September 17, 2024
Citation Information: J Clin Invest. 2024;134(21):e175790. https://doi.org/10.1172/JCI175790.
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Clinical Research and Public Health Immunology Oncology

Natural TCRs targeting KRASG12V display fine specificity and sensitivity to human solid tumors

Abstract

BACKGROUND Neoantigens derived from KRASMUT have been described, but the fine antigen specificity of T cell responses directed against these epitopes is poorly understood. Here, we explore KRASMUT immunogenicity and the properties of 4 T cell receptors (TCRs) specific for KRASG12V restricted to the HLA-A3 superfamily of class I alleles.METHODS A phase 1 clinical vaccine trial targeting KRASMUT was conducted. TCRs targeting KRASG12V restricted to HLA-A*03:01 or HLA-A*11:01 were isolated from vaccinated patients or healthy individuals. A comprehensive analysis of TCR antigen specificity, affinity, crossreactivity, and CD8 coreceptor dependence was performed. TCR lytic activity was evaluated, and target antigen density was determined by quantitative immunopeptidomics.RESULTS Vaccination against KRASMUT resulted in the priming of CD8+ and CD4+ T cell responses. KRASG12V -specific natural (not affinity enhanced) TCRs exhibited exquisite specificity to mutated protein with no discernible reactivity against KRASWT. TCR-recognition motifs were determined and used to identify and exclude crossreactivity to noncognate peptides derived from the human proteome. Both HLA-A*03:01 and HLA-A*11:01–restricted TCR-redirected CD8+ T cells exhibited potent lytic activity against KRASG12V cancers, while only HLA-A*11:01–restricted TCR-T CD4+ T cells exhibited antitumor effector functions consistent with partial coreceptor dependence. All KRASG12V-specific TCRs displayed high sensitivity for antigen as demonstrated by their ability to eliminate tumor cell lines expressing low levels of peptide/HLA (4.4 to 242) complexes per cell.CONCLUSION This study identifies KRASG12V-specific TCRs with high therapeutic potential for the development of TCR-T cell therapies.TRIAL REGISTRATION ClinicalTrials.gov NCT03592888.FUNDING AACR SU2C/Lustgarten Foundation, Parker Institute for Cancer Immunotherapy, and NIH.

Authors

Adham S. Bear, Rebecca B. Nadler, Mark H. O’Hara, Kelsey L. Stanton, Chong Xu, Robert J. Saporito, Andrew J. Rech, Miren L. Baroja, Tatiana Blanchard, Maxwell H. Elliott, Michael J. Ford, Richard Jones, Shivang Patel, Andrea Brennan, Zachary O’Neil, Daniel J. Powell Jr., Robert H. Vonderheide, Gerald P. Linette, Beatriz M. Carreno

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Figure 5

CD4+ T cells redirected with partial CD8 coreceptor–independent TCRs exhibit cytotoxic activity.

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CD4+ T cells redirected with partial CD8 coreceptor–independent TCRs exh...
(A) FACS plots demonstrating CD3 and TCR-αβ expression by TCR-engineered CD8+ (upper) and CD4+ (lower) T cells (colored) compared with nontransduced TCRnull cells (black). (B) FACS plots demonstrating pHLA multimer binding by TCR-engineered (colored) versus TCRnull (black) CD8+ (upper) and CD4+ (lower) T cells. Staining for A11Va-b is shown using 7–16V/ A11:01 multimer, while staining for A11Vc is shown using 8–16V/A11:01. Cytotoxic activity of TCR-engineered (C) CD8+ and (D) CD4+ T cells against HLA-I–matched (open) versus unmatched (filled) CORL23, SW620, and YAPC cell lines by 4-hour 51Cr-release assay. (E) KT50, defined as time (hours) to achieved 50% cytolysis at a given E:T ratio, of TCR-engineered CD8+ or CD4+ T cells against HLA-I–matched BxPC3, CORL23, SW620, and YAPC cell lines by real-time cell analysis. (F) Cytotoxic activity of primary CD8+ T cells engineered with A11Va, A11Vb, or A11Vc against CORL23 cells expressing HLA-A*11:01WT versus HLA-A*11:01D227A/T228A. Statistical comparisons were performed comparing groups at an E:T ratio of 10:1. Statistical differences between groups were calculated using 2-way ANOVA comparing percentages of GFP+ TCR-engineered JASP90_CD8+ or JASP90_CD8– cocultured with HLA-I–matched versus unmatched tumor cells followed by post hoc pairwise Student’s t test with multiple-comparison adjustment. **P < 0.01; ***P < 0.001; ****P < 0.0001.