What Happens to the Immune Microenvironment After PD-1 Inhibitor Therapy?

Front Immunol. 2021 Dec 23:12:773168. doi: 10.3389/fimmu.2021.773168. eCollection 2021.

Abstract

The fruitful results of tumor immunotherapy establish its indispensable status in the regulation of the tumorous immune context. It seems that the treatment of programmed cell death receptor 1 (PD-1) blockade is one of the most promising approaches for cancer control. The significant efficacy of PD-1 inhibitor therapy has been made in several cancer types, such as breast cancer, lung cancer, and multiple myeloma. Even so, the mechanisms of how anti-PD-1 therapy takes effect by impacting the immune microenvironment and how partial patients acquire the resistance to PD-1 blockade have yet to be studied. In this review, we discuss the cross talk between immune cells and how they promote PD-1 blockade efficacy. In addition, we also depict factors that may underlie tumor resistance to PD-1 blockade and feasible solutions in combination with it.

Keywords: PD-1 inhibitor; combined immunotherapy; cytotoxic T lymphocytes (CTLs); immunotherapy; immunotherapy resistance; tumor microenvironment.

Publication types

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

MeSH terms

  • Animals
  • Drug Resistance, Neoplasm
  • Humans
  • Immune Checkpoint Inhibitors / pharmacology*
  • Immune Checkpoint Inhibitors / therapeutic use
  • Neoplasms / drug therapy
  • Neoplasms / immunology*
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors*
  • Tumor Microenvironment / drug effects*
  • Tumor Microenvironment / immunology
  • Tumor-Associated Macrophages / drug effects

Substances

  • Immune Checkpoint Inhibitors
  • Programmed Cell Death 1 Receptor