As one of the most abundant symbiotic bacteria in the gut, Escherichia coli (E. coli) was engineered to express ClyA–Ag–mFc, of which ClyA protein was one of the most abundant proteins on the surface of OMVs, Ag was the tumor antigen, and mFc could facilitate the recognition and uptake of OMVs by DCs through the interaction between Fc and neonatal Fc receptor in DCs. Here, RENBP is linked to neoplasm.