Biomarkers for predicting efficacy of PD-1/PD-L1 inhibitors

Table 2 The role of gut microbiota in PD-1/PD-L1 inhibitors therapy

Bacteria	Main effect on immunity	Prediction of treatment effect	Model	Ref.
A. muciniphila	Increased recruitment of CCR9⁺CXCR3⁺CD4⁺ T cells into tumor bed	Effective anti-tumor response	Mouse/Human	[89]
E. hirae	Increased IL-12 secreted by DC	Effective anti-tumor response	Mouse/Human	[89]
E. faeciumC. aerofaciens B. adolescentisK. pneumoniae V. parvulaP. merdae Lactobacillus sp. B. longum	Increased neoantigen specific CD8⁺ T cell and decreased Fox3P⁺CD4⁺ Treg in tumor microenvironment	Effective anti-tumor response	Mouse/Human	[134]
Bifidobacterium	Increased IFN-γ production and major histocompatibility complex Class II^hi DC	Effective anti-tumor response	Mouse	[87]
Faecalibacterium	Increased peripheral effector CD4⁺ and CD8⁺ T cell	Effective anti-tumor response	Mouse/Human	[88]
Bacteroidales	Increased peripheral Treg and myeloid derived suppressor cell	Poor anti-tumor response	Mouse/Human	[88]

Abbreviations: IFN-γ interferon-γ, Treg regulatory T cell, DC dendritic cell

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