Journal for ImmunoTherapy of Cancer (Feb 2019)

Efficacy of PD-1 blockade in cervical cancer is related to a CD8+FoxP3+CD25+ T-cell subset with operational effector functions despite high immune checkpoint levels

  • A. M. Heeren,
  • J. Rotman,
  • A. G. M. Stam,
  • N. Pocorni,
  • A. A. Gassama,
  • S. Samuels,
  • M. C. G. Bleeker,
  • C. H. Mom,
  • H. J. M. A. A. Zijlmans,
  • G. G. Kenter,
  • E. S. Jordanova,
  • T. D. de Gruijl

DOI
https://doi.org/10.1186/s40425-019-0526-z
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 14

Abstract

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Abstract Background Cervical cancer (CxCa) is mainly a locally invading disease that metastasizes to loco-regional lymph node basins before involving distant organs in more advanced stages. Local immune potentiation of tumor-draining lymph nodes (TDLN) may thus protect against tumor progression. Methods To identify therapeutic targets for local immune modulation, multi-parameter flow cytometric T-cell profiling of primary cervical tumors (PT) and TDLN (n = 37) was performed. The in-vitro effect of PD-1 blockade on T-cell reactivity to HPV16 E6 oncoproteins was determined in cultures of TDLN and PT single cell suspensions (n = 19). Also, intracellular cytokine staining (ICS) upon anti-CD3 stimulation was performed in metastatic TDLN (LN+) and PT (n = 7), as well as multiplexed immunofluorescence histochemistry staining (n = 8). Results Our data revealed elevated rates of activated regulatory T cells (aTregs) and of central or effector memory CD8+ T cells in metastatic TDLN (LN+) as compared to tumor-free TDLN (LN-), and equally high or even higher rates of these subsets in PT. Both memory subsets co-expressed multiple immune checkpoints. PD-1 blockade significantly enhanced detectable E6-specific T-cell responses in 4/5 HPV16+ LN+ and in 1/5 HPV16+ PT. Whereas aTreg rates were higher in anti-PD-1 non-responders, in responders elevated levels of CD8+FoxP3+CD25+ T cells were observed, which correlated with the efficacy of PD-1 blockade (P = 0.018). This subset was characterized by an early effector memory phenotype with particularly high levels of co-expressed PD-1, CTLA-4, TIM-3 and LAG-3 checkpoints, but, rather than exhausted, was shown upon polyclonal activation to produce higher levels of Granzyme-B and effector cytokines as compared to its CD8+FoxP3− counterparts. Conclusion These observations support local PD-(L)1 blockade to interrupt loco-regional immune suppression in CxCa and control metastatic spread to TDLN. Furthermore, our data identify CD8+FoxP3+CD25+ T cells as therapeutic targets, which may also serve as predictive biomarker for PD-(L)1 checkpoint blockade.

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