Definition of TCR Epitopes for CTL-Mediated Attack of Cutaneous T Cell Lymphoma

Abstract

Therapeutic vaccination against cutaneous T cell lymphoma (CTCL) requires the characterization of cancer cell-specific CTL epitopes. Despite reported evidence for tumor-reactive cytotoxicity in CTCL patients, the nature of the recognized determinants remains elusive. The clonotypic TCR of CTCL cells is a promising candidate tumor-specific Ag. In this study, we report that the clonotypic and framework regions of the TCRs expressed in the malignant T cell clones of six CTCL patients contain multiple peptides with anchor residues fitting the patients’ MHC class I molecules. We demonstrate that TCR peptide-specific T cells from the blood of healthy donors and patients can be induced to become cytotoxic effectors after repeated stimulation with 6 of 11 selected peptides with experimentally proven affinity for HLA-A*0201. Importantly, 4 of these 6 CTL lines reproducibly recognize and lyse autologous primary CTCL cells in MHC class I/CD8-dependent fashion. These tumoricidal CTL lines are directed against epitopes from V, hypervariable, and C regions of TCRα. We therefore conclude that recombined as well as V framework regions of the tumor cell TCRs contain predictable epitopes for CTL-mediated attack of CTCL cells. Our data further suggest that such peptides represent valuable tools for future anti-CTCL vaccination approaches.

Down-Modulation of CXCR3 Surface Expression and Function in CD8+ T Cells from Cutaneous T Cell Lymphoma Patients

“…Candidate epitopes recognized by these lymphoma-specific CTL include variable and hypervariable regions of the clonal TCR and cancer-related Ags of the tumor/testis family (6 -9). Interestingly, lymphoma-specific cytotoxic T cell responses of comparable specificity and magnitude could be induced from the blood of healthy controls and of lymphoma patients with a far advanced disease (6). This indicates that deletion or permanent anergy of lymphoma-specific circulating CD8 ϩ T cells is not a viable explanation for a loss of immunologic control resulting in disease progression.…”

“…The diagnosis of mycosis fungoides was based on clinical criteria, typical histology, and immunohistology in accordance with the classification of cutaneous lymphomas by the European Organization for Research and Treatment of Cancer (12). T cell clonality in skin and/or blood was determined by a standard multiplex PCR approach and/or by mAb-based anti-TCRV␤ immunophenotyping (6). Blood and lesional skin were obtained from one patient with varicella zoster virus (VZV) infection.…”

“…Cells from CTCL tumor lesions and VZV-induced skin lesions were isolated, as described previously (6). Briefly, punch biopsies were minced and cells were squeezed out by applying gentle manual pressure.…”

“…K-562 cells were labeled with Eu 3ϩ , as described previously (6,14). Briefly, 5 ϫ 10 6 cells were incubated on ice for 15 min in 1 ml of labeling buffer (0. ϩ glucose (Sigma-Aldrich) and 2 mM CaCl 2 .…”

Anti‐tumor immune responses and tumor regression induced with mimotopes of a tumor‐associated T cell epitope

“…Pleomorphic large cell CD30 + CTCL, in contrast, is characterized by tumor nodules, low malignancy, and slow progression. Despite intense efforts, only a few T cell epitopes have been described for these malignancies, all derived from the TCR of the tumor cells and determined by epitope mapping of their sequences [16,17]. We employed a combinatorial peptide library approach to determine mimotopes for a CTCL-specific CD8 + T cell clone [18].…”