Tumor cells fail to present MHC-II–restricted epitopes derived from oncogenes to CD4+ T cells
Spencer E. Brightman, … , Aaron M. Miller, Stephen P. Schoenberger
Spencer E. Brightman, … , Aaron M. Miller, Stephen P. Schoenberger
Published December 13, 2022
Citation Information: JCI Insight. 2023;8(2):e165570. https://doi.org/10.1172/jci.insight.165570.
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Research Article Immunology Oncology

Tumor cells fail to present MHC-II–restricted epitopes derived from oncogenes to CD4+ T cells

Abstract

CD4+ T cells play a critical role in antitumor immunity via recognition of peptide antigens presented on MHC class II (MHC-II). Although some solid cancers can be induced to express MHC-II, the extent to which this enables direct recognition by tumor-specific CD4+ T cells is unclear. We isolated and characterized T cell antigen receptors (TCRs) from naturally primed CD4+ T cells specific for 2 oncoproteins, HPV-16 E6 and the activating KRASG12V mutation, from patients with head and neck squamous cell carcinoma and pancreatic ductal adenocarcinoma, respectively, and determined their ability to recognize autologous or human leukocyte antigen–matched antigen-expressing tumor cells. We found in both cases that the TCRs were capable of recognizing peptide-loaded target cells expressing the relevant MHC-II or B cell antigen-presenting cells (APCs) when the antigens were endogenously expressed and directed to the endosomal pathway but failed to recognize tumor cells expressing the source protein even after induction of surface MHC-II expression by IFN-γ or transduction with CIITA. These results suggest that priming and functional recognition of both a nuclear (E6) and a membrane-associated (KRAS) oncoprotein are predominantly confined to crosspresenting APCs rather than via direct recognition of tumor cells induced to express MHC-II.

Authors

Spencer E. Brightman, Martin S. Naradikian, Rukman R. Thota, Angelica Becker, Leslie Montero, Milad Bahmanof, Ashmitaa Logandha Ramamoorthy Premlal, Jason A. Greenbaum, Bjoern Peters, Ezra E.W. Cohen, Aaron M. Miller, Stephen P. Schoenberger

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Figure 2

Functional characteristics of an HLA-A*02:01–restricted, E6-specific TCR from Hu-56 TILs.

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Functional characteristics of an HLA-A*02:01–restricted, E6-specific TCR...
(A) Histogram demonstrating 1 μg/mL HLA-A*02:01/E629-38 tetramer binding to Jurkat cells expressing an irrelevant TCR, a previously described TCR with known E6 specificity, or the TCR identified among the dominant CD8+ clonotype in patients’ TILs. (B) Representative FACS plots demonstrating specific upregulation of CD69 on Jurkat cells when stimulated with 1 μg/mL E629-38 peptide. (C) Functional avidity curves comparing activation of TCR-expressing Jurkat cells stimulated with a titration of peptide concentrations. Data are presented as the mean ± SEM of 3 independent experiments. NCI, National Cancer Institute TCR. (D) Cellular impedance measurements to determine the kinetics of tumor cell death after recognition of CaSki cells by primary human T cells expressing the F29 TCR compared with mock-transduced donor T cells. Normalized cell index values over time for effector to target (E:T) ratios 10:1, 3:1, and 1:1 are shown compared with tumor cells cultured without effectors. Data are presented as mean values of 3 technical replicates ± SEM and are representative of 2 independent experiments. (E) Cellular impedance measurements to determine the kinetics of tumor cell death after recognition of an autologous HNSCC-56 tumor cell line by primary human T cells expressing the F29 TCR compared with mock-transduced donor T cells. Normalized cell index values over time for E:T ratios 10:1, 3:1, and 1:1 are shown compared with tumor cells cultured without effectors. Data are presented as mean values of 3 technical replicates ± SEM and are representative of 2 independent experiments.