Engineered Escherichia coli for the in situ secretion of therapeutic nanobodies in the gut

Summary

Drug platforms that enable the directed delivery of therapeutics to sites of diseases to maximize efficacy and limit off-target effects are needed. Here, we report the development of PROT₃EcT, a suite of commensal Escherichia coli engineered to secrete proteins directly into their surroundings. These bacteria consist of three modular components: a modified bacterial protein secretion system, the associated regulatable transcriptional activator, and a secreted therapeutic payload. PROT₃EcT secrete functional single-domain antibodies, nanobodies (Nbs), and stably colonize and maintain an active secretion system within the intestines of mice. Furthermore, a single prophylactic dose of a variant of PROT₃EcT that secretes a tumor necrosis factor-alpha (TNF-α)-neutralizing Nb is sufficient to ablate pro-inflammatory TNF levels and prevent the development of injury and inflammation in a chemically induced model of colitis. This work lays the foundation for developing PROT₃EcT as a platform for the treatment of gastrointestinal-based diseases.