Presented by: Jason P. Lynch
New drug platforms are needed which enable the directed delivery of therapeutics to sites of disease to maximize efficacy and limit off-target effects. Here, we report the development of PROT3EcT, commensal Escherichia coli engineered for the direct secretion of proteins into their surroundings. PROT3EcT is composed of four modular components: an E. coli chassis, a modified bacterial protein secretion system, a regulatable transcriptional activator, and a secretable therapeutic payload. We demonstrate that PROT3EcT can secrete fully functional payloads, including single-domain antibodies nanobodies (Nb), into the extracellular space. Nb-secreting PROT3EcT stably colonizes and maintains a functional secretion system within the intestines of mice. A single prophylactic dose of PROT3EcT that secretes a tumor necrosis factor-alpha (TNFα) neutralizing Nb, but not PROT3EcT alone, is sufficient to ablate TNF levels and prevent the development of injury and inflammation in a chemically-induced model of inflammatory bowel disease. This work lays the foundation for the development of PROT3EcT as a therapeutic platform for the treatment of at least gastrointestinal-based diseases.