Intratumoral accumulation of gut #microbiota facilitates CD47-based immunotherapy via STING signaling

..Using one defined anaerobic gut microbiota to track whether microbiota interact with host immunity, we observed that Bifidobacterium facilitates local anti-CD47 immunotherapy on tumor tissues through the capacity to accumulate within the tumor microenvironment.

Systemic administration of Bifidobacterium leads to its accumulation within the tumor and converts the nonresponder mice into responders to anti-CD47 immunotherapy in a stimulator of interferon genes (STING)– and interferon-dependent fashion. Local delivery of Bifidobacterium potently stimulates STING signaling and increases cross-priming of dendritic cells after anti-CD47 treatment.

Our study identifies the mechanism by which gut microbiota preferentially colonize in tumor sites and facilitate immunotherapy via STING signaling.