Stanford (Calif.) Medicine and Cambridge-based MIT researchers found a common bacteria may help eliminate skin cancer.
The study, published April 13 in Science, used genetically engineered Staphylococcus epidermidis on mice with cancer. Staph epidermidis is a bacteria that lives on healthy skin and triggers the production of immune cells called CD8 T cells, according to an April 12 Stanford news release. These "killer" cells are responsible for battling severe infections or cancer.
"It seemed almost like magic," Michael Fischbach, PhD, an associate professor of bioengineering at Stanford Medicine, said in the release. "These mice had very aggressive tumors growing on their flank, and we gave them a gentle treatment where we simply took a swab of bacteria and rubbed it on the fur of their heads."
By inserting a tumor antigen into the bacteria, researchers tricked the mouse's immune system into producing CD8 T cells. These cells rapidly proliferated when they encountered a matching tumor, drastically slowing the growth or eliminating it altogether.
Researchers then injected healthy mice with melanoma tumor cells. The mice given genetically engineered Staph epidermidis grew tumors at a slower rate or in some cases, grew no tumors. Scientists found T cells in the skin, spleen and slow-growing tumors, meaning T cells generated by colonizing bacteria must carry the same immune potential as regular killer T cells, Dr. Fischbach said.