TIGIT and PD-1 impair tumor antigen-specific CD8⁺ T cells in melanoma patients

J Clin Invest. 2015 May;125(5):2046-58. doi: 10.1172/JCI80445. Epub 2015 Apr 13.


T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen-specific (TA-specific) CD8⁺ T cells and CD8⁺ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8⁺ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8⁺ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1⁺TIM-3⁺ TA-specific CD8⁺ T cells. PD-1⁺TIGIT⁺, PD-1⁻TIGIT⁺, and PD-1⁺TIGIT⁻ CD8⁺ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand-expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8⁺ T cells and CD8⁺ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8⁺ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8⁺ T cell responses in patients with advanced melanoma.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • Antigen-Presenting Cells / immunology
  • Antigen-Presenting Cells / metabolism
  • Antigens, Differentiation, T-Lymphocyte / biosynthesis
  • Antigens, Differentiation, T-Lymphocyte / genetics
  • Antigens, Neoplasm / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Line, Tumor
  • Cytokines / biosynthesis
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunologic Memory
  • Immunophenotyping
  • Interleukin-2 Receptor beta Subunit / biosynthesis
  • Interleukin-2 Receptor beta Subunit / genetics
  • Lymphocyte Activation
  • Lymphocytes, Tumor-Infiltrating / immunology*
  • Lymphocytes, Tumor-Infiltrating / metabolism
  • Melanoma / immunology*
  • Melanoma / pathology
  • Neoplasm Proteins / antagonists & inhibitors
  • Neoplasm Proteins / biosynthesis
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / physiology*
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors
  • Programmed Cell Death 1 Receptor / biosynthesis
  • Programmed Cell Death 1 Receptor / genetics
  • Programmed Cell Death 1 Receptor / physiology*
  • Receptors, Immunologic / antagonists & inhibitors
  • Receptors, Immunologic / biosynthesis
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / physiology*
  • Receptors, Virus / biosynthesis
  • Receptors, Virus / genetics
  • T-Cell Antigen Receptor Specificity
  • Up-Regulation


  • Antibodies, Monoclonal
  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Neoplasm
  • CD226 antigen
  • Cytokines
  • IL2RB protein, human
  • Interleukin-2 Receptor beta Subunit
  • Neoplasm Proteins
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Receptors, Immunologic
  • Receptors, Virus
  • TIGIT protein, human
  • poliovirus receptor