Engineered probiotic bacteria deliver targeted IL-2 therapy to shrink pancreatic tumors

A multidisciplinary team at the University of Chicago created BifidoSumIL-2, an engineered strain of the probiotic Bifidobacterium longum programmed to release a modified interleukin-2 (SumIL-2) directly inside pancreatic tumors. Because the bacterium thrives in anaerobic environments, it accumulates in the oxygen-poor regions of solid tumors and produces SumIL-2, which selectively stimulates CD8⁺ T cells while limiting regulatory T-cell activation.

In animal models, this strategy slowed tumor growth and extended survival, with even greater benefit when combined with chemotherapy, radiation or anti-PD-L1 immunotherapy. Researchers noted the technical difficulty of modifying Bifidobacterium but emphasized its favorable safety profile as a common probiotic. Published in Science Advances, the study proposes a new “bugs as drugs” method to improve pancreatic cancer treatment, pending human safety and efficacy studies. Funding was provided by the Ludwig Foundation and the National Institutes of Health.