PD-L1/B7H-1 Inhibits the Effector Phase of Tumor Rejection by T Cell Receptor (TCR) Transgenic CD8+ T Cells

Christian Blank, Ian Elliott Brown, Amy C. Peterson, Mike Spiotto, Yoshiko Iwai, Tasuku Honjo, Thomas F. Gajewski

Research output: Contribution to journalArticlepeer-review

595 Scopus citations


Although increased circulating tumor antigen-specific CD8+ T cells can be achieved by vaccination or adoptive transfer, tumor progression nonetheless often occurs through resistance to effector function. To develop a model for identifying mechanisms of resistance to antigen-specific CTLs, poorly immunogenic B16-F10 melanoma was transduced to express the K b-binding peptide SIYRYYGL as a green fluorescent protein fusion protein that should be recognized by high-affinity 2C TCR transgenic T cells. Although B16.SIY cells expressed high levels of antigen and were induced to express Kb in response to IFN-γ, they were poorly recognized by primed 2C/RAG2-/- T cells. A screen for candidate inhibitory ligands revealed elevated PD-L1/B7H-1 on IFN-γ-treated B16-F10 cells and also on eight additional mouse tumors and seven human melanoma cell lines. Primed 2C/RAG2-/-/PD-1-/- T cells showed augmented cytokine production, proliferation, and cytolytic activity against tumor cells compared with wild-type 2C cells. This effect was reproduced with anti-PD-L1 antibody present during the effector phase but not during the priming culture. Adoptive transfer of 2C/RAG2-/-/PD-1-/- T cells in vivo caused tumor rejection under conditions in which wild-type 2C cells or CTLA-4-deficient 2C cells did not reject. Our results support interfering with PD-L1/PD-1 interactions to augment the effector function of tumor antigen-specific CD8+ T cells in the tumor microenvironment.

Original languageEnglish (US)
Pages (from-to)1140-1145
Number of pages6
JournalCancer Research
Issue number3
StatePublished - Feb 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • Cancer Research
  • Oncology


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