TCR Analyses of Two Vast and Shared Melanoma Antigen-Specific T Cell Repertoires: Common and Specific Features

Front Immunol. 2018 Aug 30;9:1962. doi: 10.3389/fimmu.2018.01962. eCollection 2018.

Abstract

Among Immunotherapeutic approaches for cancer treatment, the adoptive transfer of antigen specific T cells is still a relevant approach, that could have higher efficacy when further combined with immune check-point blockade. A high number of adoptive transfer trials have been performed in metastatic melanoma, due to its high immunogenic potential, either with polyclonal TIL or antigen-specific polyclonal populations. In this setting, the extensive characterization of T cell functions and receptor diversity of infused polyclonal T cells is required, notably for monitoring purposes. We developed a clinical grade procedure for the selection and amplification of polyclonal CD8 T cells, specific for two shared and widely expressed melanoma antigens: Melan-A and MELOE-1. This procedure is currently used in a clinical trial for HLA-A2 metastatic melanoma patients. In this study, we characterized the T-cell diversity (T-cell repertoire) of such T cell populations using a new RNAseq strategy. We first assessed the added-value of TCR receptor sequencing, in terms of sensitivity and specificity, by direct comparison with cytometry analysis of the T cell populations labeled with anti-Vß-specific antibodies. Results from these analyzes also confirmed specific features already reported for Melan-A and MELOE-1 specific T cell repertoires in terms of V-alpha recurrence usage, on a very high number of T cell clonotypes. Furthermore, these analyses also revealed undescribed features, such as the recurrence of a specific motif in the CDR3α region for MELOE-1 specific T cell repertoire. Finally, the analysis of a large number of T cell clonotypes originating from various patients revealed the existence of public CDR3α and ß clonotypes for Melan-A and MELOE-1 specific T cells. In conclusion, this method of high throughput TCR sequencing is a reliable and powerful approach to deeply characterize polyclonal T cell repertoires, and to reveal specific features of a given TCR repertoire, that would be useful for immune follow-up of cancer patients treated by immunotherapeutic approaches.

Keywords: MELOE-1; Melan-A; TCR sequencing; immunotherapy; melanoma.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer*
  • Antigens, Neoplasm* / genetics
  • Antigens, Neoplasm* / immunology
  • Female
  • High-Throughput Nucleotide Sequencing*
  • Humans
  • MART-1 Antigen* / genetics
  • MART-1 Antigen* / immunology
  • Male
  • Melanoma* / genetics
  • Melanoma* / immunology
  • Melanoma* / pathology
  • Melanoma* / therapy
  • Neoplasm Proteins* / genetics
  • Neoplasm Proteins* / immunology
  • Receptors, Antigen, T-Cell, alpha-beta / genetics
  • Receptors, Antigen, T-Cell, alpha-beta / immunology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology

Substances

  • Antigens, Neoplasm
  • MART-1 Antigen
  • MELOE-1 antigen, human
  • Neoplasm Proteins
  • Receptors, Antigen, T-Cell, alpha-beta