A study in mice suggests that by infiltrating tumors and ramping up the body’s immune response, a type of gut bacteria could be a valuable ally in cancer treatment.
In recent years, research has shown that the communities of bacteria that live in our guts — known as our gut microbiota — play crucial roles not only in disease but also in promoting health.
Some research has found beneficial effects of probiotic “friendly” bacteria on the immune system.
For example, one study suggested that a species of Bifidobacterium can modify the body’s immune responses in psoriasis, ulcerative colitis, and chronic fatigue syndrome. Another found evidence that a combination of Bifidobacteria and Lactobacilli can relieve hay fever.
The authors of the new study, which features in the Journal of Experimental Medicine, note that certain bacteria have also demonstrated the ability to improve the efficacy of cancer immunotherapy by activating gut immunity.
They report that in their research on mice, they discovered that various species of Bifidobacterium can find their way into gut tumors even after being injected.
Once inside the tumors, the bacteria seem to activate the wider immune system and, in the process, enhance a type of cancer treatment called CD47 blockade immunotherapy.
One of the molecular tricks that tumors deploy to evade attacks by the immune system is to incorporate a protein called CD47 into their cell membranes.
In their paper, the researchers describe CD47 as a “don’t eat me” signal to macrophages, a scavenger type of immune cell that engulfs invading cells, including cancerous ones. Several ongoing clinical