Some types of gut bacteria are better than others at stimulating certain immune cells, specifically CD8+ T cells. And while these CD8+ T cells normally help protect the body against cancer, overstimulating them may promote inflammation and exhaust the T cells — which can actually increase susceptibility to cancer, according to new mouse model.

Some types of gut bacteria are better than others at stimulating certain immune cells, specifically CD8+ T cells, in the body, they found. And while these CD8+ T cells normally help protect the body against cancer, overstimulating them may promote inflammation and exhaust the T cells — which can actually increase susceptibility to cancer, according to new mouse model study published in Cell Reports.

The work will help scientists pinpoint which populations of bacteria are tumor suppressive or tumor promoting and how, says study first author Amy Yu, a doctoral candidate in immunology at U-M.

«There has also been a lot of excitement about the role bacteria may play in improving the effectiveness of immunotherapy,» says senior study author Grace Chen, M.D., Ph.D., an associate professor of hematology/oncology at Michigan Medicine and member of the Rogel Cancer Center. «This work suggests it may be a double edged sword — and that promoting T cell exhaustion is something researchers need to watch out for.»

In the U.S., colorectal cancer is the third-leading cause of cancer-related death in both men and women, according to the American Cancer Society.

Different mice, different outcomes

The current study builds on previous work from Chen’s group, which found that disturbances of the gut microbiome can directly contribute to the development of cancer.

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Materials provided by Michigan Medicine — University of Michigan. Note: Content may be edited for style and length.