Figure 6.

Proposed mechanism of the effect of MS-20.

Note: The symbiota MS-20 exhibited antitumor activity in combination with an anti-PD1 antibody. Treatment with MS-20 FMT enhanced the efficacy of anti-PD1 therapy and promoted the entry of CD8⁺ T cells into the tumor microenvironment. The abundances of distinct MS-20-regulated bacteria, such as R. bromii, were correlated with antitumor activity and CD8⁺ T-cell infiltration. MS-20 also regulated intestinal immunity through the upregulation of CCL19, CCL21 and defensin expression, which have been found to recruit and activate dendritic cells. These data suggested that MS-20 elicited antitumor activity in combination with anti-PD1 therapy by modulating the immune-associated gut microbiota and intestinal immunity. The figure was created with BioRender.com.