Parasite Discovered in Cat Poop Could Combat Cancer

Could a parasite found in cat poop help cancer research? It just might be able to, according to a new study. Scientists have found that Toxoplasma gondii (T. gondii), a single-celled parasite that's happiest in a cat's intestines, causes a person's immune system to react in a similar manner to when it attacks a tumor.

"We know biologically this parasite has figured out how to stimulate the exact same responses you want to fight cancer," said David J. Bzik, one of the researchers, in a news release.

When T. gondii infects a person, the body produces natural killer cells and cytotoxic T cells. These cells are the same type that wage war against cancer cells. While cancer can shut down the body's defensive mechanisms, though, T. gondii could potentially jump start the immune system.

The researchers created "cps," which is an immunotherapeutic vaccine. Basing it on the parasite's biochemical pathways, they deleted a Toxoplasma gene needed to make a building block of its genome and created a mutant parasite that could be grown in the laboratory but couldn't reproduce in animals or people.

"The biology of this organism is inherently different from other microbe-based immunotherapeutic strategies that typically just tickle immune cells from the outside," said Barbara Fox, senior research associate of Microbiology and Immunology. "By gaining preferential access to the inside of powerful innate immune cell types, our mutation strain of T. gondii  reprograms the natural power of the immune system to clear tumor cells and cancer."

The cps vaccine could potentially help with cancer survival. Already, the scientists have tested the vaccine in extremely aggressive lethal mouse models of melanoma or ovarian cancer.

"Cps stimulates amazingly effective immunotherapy against cancers, superior to anything seen before," said Bzik. "The ability of cps to communicate in different and unique ways with the cancer and special cells of the immune system breaks the control that cancer has leveraged over the immune system."

Currently, the researchers need to study cps quite a bit more before it leaves the lab. Yet it does present a possible way to help fight cancer in the future.