Berkeley Scientists Turn Food Poisoning Bug Into Cancer Fighter

Scientists at UC Berkeley just turned one of nature's nastiest bugs into a potential lifesaver for kids battling cancer.

For nearly four decades, Daniel Portnoy studied Listeria, the bacteria that causes serious food poisoning. He learned exactly how it sneaks past our immune defenses and hides inside our cells. Now he's flipped that knowledge on its head.

Three years ago, Portnoy cofounded Laguna Biotherapeutics to engineer a version of Listeria that can't make people sick but still supercharges a special type of immune cell. These gamma delta T cells act like the body's SWAT team, hunting down and destroying cancer cells or any cell infected by disease.

The engineered bacteria work differently than current cancer treatments. Most immunotherapies boost the adaptive immune system, training it to recognize specific cancer cells. But tumors are sneaky and create environments that shut down immune responses.

Listeria therapy takes another approach. The modified bacteria wake up the body's innate immune system, the first line of defense that responds to anything foreign. Because the bacteria trigger such a strong natural alarm, they help the body overcome the tumor's immune suppression.

Portnoy's team removed two genes from Listeria that let it spread between cells. The bacteria can still enter immune cells and sound the alarm, but they can't escape and cause illness. It's like creating a fire drill that activates all the safety systems without any actual danger.

The therapy recently showed promising results in mice, published in the journal mBio. Now doctors at Stanford University Medical Center want to test it in children with leukemia who receive bone marrow transplants from unmatched donors.

These young patients face three major threats: graft versus host disease where donor cells attack their body, deadly infections because their immune system is compromised, and cancer returning. The boosted gamma delta T cells could help fight all three at once.

Why This Inspires

This story shows how patient, persistent research can transform our understanding of disease. Portnoy spent four decades studying how one bacteria causes harm. That deep knowledge became the key to creating something healing.

The therapy could eventually help patients with many types of cancer, not just leukemia. The researchers also discovered they can engineer Listeria to boost other infection-fighting immune cells called MAIT cells.

"We believe that if you want to generate a comprehensive immune response, you need to carefully orchestrate the entire immune system," said Jonathan Kotula, CEO of Laguna Biotherapeutics. "And attenuated Listeria seems to be doing that."

The team will soon ask the FDA for permission to begin human trials.

Forty years of studying how bacteria outsmart us just might teach us how to outsmart cancer.