Development of a T Cell Receptor Targeting an HLA-A*0201 Restricted Epitope from the Cancer-Testis Antigen SSX2 for Adoptive Immunotherapy of Cancer

Daniel Abate-Daga,Daniel E Speiser,Nachimuthu Chinnasamy,Richard A Morgan,Zhili Zheng,Steven A Feldman,Steven A Rosenberg,Hui Xu,Nupur Gangopadhyay

doi:10.1371/journal.pone.0093321

Daniel Abate-Daga, Daniel E Speiser + Show 7 more

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https://doi.org/10.1371/journal.pone.0093321

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Abstract

The clinical success of adoptive immunotherapy of cancer relies on the selection of target antigens that are highly expressed in tumor cells but absent in essential normal tissues. A group of genes that encode the cancer/testis or cancer germline antigens have been proposed as ideal targets for immunotherapy due to their high expression in multiple cancer types and their restricted expression in immunoprivileged normal tissues. In the present work we report the isolation and characterization of human T cell receptors (TCRs) with specificity for synovial sarcoma X breakpoint 2 (SSX2), a cancer/testis antigen expressed in melanoma, prostate cancer, lymphoma, multiple myeloma and pancreatic cancer, among other tumors. We isolated seven HLA-A2 restricted T cell receptors from natural T cell clones derived from tumor-infiltrated lymph nodes of two SSX2-seropositive melanoma patients, and selected four TCRs for cloning into retroviral vectors. Peripheral blood lymphocytes (PBL) transduced with three of four SSX2 TCRs showed SSX241-49 (KASEKIFYV) peptide specific reactivity, tumor cell recognition and tetramer binding. One of these, TCR-5, exhibited tetramer binding in both CD4 and CD8 cells and was selected for further studies. Antigen-specific and HLA-A*0201-restricted interferon-γ release, cell lysis and lymphocyte proliferation was observed following culture of TCR engineered human PBL with relevant tumor cell lines. Codon optimization was found to increase TCR-5 expression in transduced T cells, and this construct has been selected for development of clinical grade viral vector producing cells. The tumor-specific pattern of expression of SSX2, along with the potent and selective activity of TCR-5, makes this TCR an attractive candidate for potential TCR gene therapy to treat multiple cancer histologies.

Highlights

Recent advances in the fields of tumor immunology, cancer genomics and gene transfer technologies have permitted the development of therapies based on adoptive transfer of autologous tumor-reactive T cells for the treatment of human malignancies [1,2]
In order to expand the repertoire of antigens that can be targeted by this approach, expanding the number of patients and tumor types that can be treated, we developed a T cell receptors (TCRs)-expressing vector targeting a member of the synovial sarcoma X breakpoint family, synovial sarcoma X breakpoint 2 (SSX2)
Expression and correct assembly of TCRs was evaluated by flow cytometry, using fluorescently labeled HLA-A2-SSX241-49 tetramers

Summary

Introduction

Recent advances in the fields of tumor immunology, cancer genomics and gene transfer technologies have permitted the development of therapies based on adoptive transfer of autologous tumor-reactive T cells for the treatment of human malignancies [1,2]. Tumor-reactive T cells can be natural, as in the case of tumor infiltrating lymphocytes (TIL) purified from resected lesions and stimulated ex vivo, or generated from peripheral blood by introduction of genes encoding for immune receptors [3]. Adoptive transfer of autologous T cells engineered to express T cell receptors (TCRs) or antibody-derived chimeric immune receptors can result in a potent cellular immune response against tissues expressing the target antigens, even at low levels [3,6,7,8]. It is instrumental to carefully select antigens that are expressed in tumor cells but absent from essential normal tissues, in order to avoid undesired on-target/off-tumor toxicities

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