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Updated: Aug 5, 2026

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing
11:22

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing

Published on: October 15, 2019

Regulation of PD-1PD-L1 Immune Checkpoints by Gut Microbiota Metabolites and Their Clinical Translational Research: A

Xuanyou Fang1, Shuai Yuan1, Weijian Mai1

  • 1Xiaolan Clinical Institute of Shantou University Medical College, Zhongshan, Guangdong Province, China.

Immunity, Inflammation and Disease
|July 29, 2026
PubMed
Abstract

Insights

Gut microbiota metabolites like SCFAs, tryptophan metabolites, and bile acids significantly impact cancer immunotherapy by modulating the PD-1/PD-L1 axis. These metabolites offer potential as biomarkers and therapeutic targets to improve treatment efficacy.

Area of Science:

  • Immunology
  • Microbiome Research
  • Cancer Therapy

Background:

  • Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 pathway have transformed cancer treatment.
  • However, variable response rates and immune-related adverse events limit their clinical utility.

Purpose of the Study:

  • To systematically review how gut microbiota metabolites influence the PD-1/PD-L1 axis.
  • To analyze molecular mechanisms of short-chain fatty acids (SCFAs), tryptophan metabolites, and bile acids in cancer immunotherapy.

Main Methods:

  • Comprehensive literature search of preclinical and clinical studies over the last decade.
  • Focus on metabolite-immune interactions, biomarker validation, and combination therapy strategies.

Main Results:

  • Gut microbiota metabolites significantly impact the tumor microenvironment and T-cell functions.
  • These metabolites influence immune tolerance and affect responsiveness to ICIs.
  • Evidence supports their role in enhancing anti-tumor immunity.

Conclusions:

  • Microbiota metabolites show promise as predictive biomarkers for ICI therapy.
  • Probiotic, fecal microbiota transplantation, and metabolite-based therapies are under investigation.
  • Further research is needed to address variability and mechanistic gaps for clinical integration.
Keywords:
PD‐1PD‐L1cancer immunotherapyclinical translationgut microbiotaimmune checkpoint inhibitorsmetabolites

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