Intestinal flora increases the anti-PD-1 therapeutic effect by regulating immune cells.

Akkermansia muciniphila accelerated the activity of CXCR3+CCR9+CD4+T cells, produced more IFN-γ. Bacteroidalesinhibited the infiltration of B cells and T cells. Bifidobacterium and Olsenella produced metabolites inosine and increase the levels of interleukin-12 (IL-12), interferon γ (IFN-γ) , TNF-a and interleukin-2 (IL-2). Bifidobacterium bifidumpromotes the activation of T cells and B cells. Enterococcus faecium releases the metabolite SagA, produces NOD2 active polypeptide, and promotes the activation of B cells, T cells. Enterococcus hirae promotes tumor cell apoptosis, weakens the proliferation and migration of tumor cells, promotes the infiltration of T cells, B cells, promotes the activation of CD8+ T cells. Faecalibacterium promotes the activation of CD8+ T cells. Lactobacillus rhamnosus GG (LGG), induces IFN-β production, promotes CD8+ T cell activation via the cGAS/STING pathway in DC. Lactobacillus johnsoniienhances the immunotherapy effect through the metabolite hypoxanthine. Ruminococcaceae increases the number of effector T cells, induces the activation of effector CD4+ and CD8+ T cells, increases tumor CD8+ T cell infiltration.