BIOBRIEF
A University of Chicago team programmed a gut bacterium to release a T cell signal inside pancreatic tumors, where the construct worked best alongside chemo, radiation, or immunotherapy; it has not been tested in people.
A University of Chicago team turned a common gut bacterium into a microscopic drug factory for pancreatic cancer, [according to a study in Science Advances](https://www.science.org/doi/10.1126/sciadv.adz1388).
The researchers engineered Bifidobacterium longum, a microbe found in yogurt, to secrete a modified interleukin-2, an immune signal that activates cancer-killing T cells. The variant, SumIL-2, was tuned to favor effector T cells over regulatory T cells, which dampen immune responses.
Because B. longum is an obligate anaerobe, it thrives in low-oxygen environments and dies in healthy tissue. That biology lets it self-concentrate inside the oxygen-starved core of pancreatic tumors. UChicago reported that in mouse models, the construct increased CD8+ T cell activity and slowed tumor growth.
The standalone effect was modest. Pairing BifidoSumIL-2 with chemotherapy, radiotherapy, or anti-PD-L1 checkpoint inhibitors produced a stronger response than any single treatment. Co-author Mark Mimee called the bacterium "the delivery vehicle" and the combination "the actual advance," per the university's release.
Pancreatic cancer kills most patients within a year of diagnosis and has resisted immunotherapy because its tumors hide from immune attack. The approach, republished by ScienceDaily, is one of several preclinical attempts to crack that problem. No human trials have been reported; durability and safety remain open.