Bacterial Immune Chemotherapy

Bacterial Immune Chemotherapy

The interwoven nature of our gut microbiome with the functioning of our immune system never ceases to amaze me.  Researchers at the University of Calgary recently reported another potential life-saving discovery.  Specific gut bacteria may enhance the efficacy of cancer immunotherapy in several cancer types.  Besides correlating the presence of Bifidobacterium pseudolongum, Lactobacillus johnsonii and Olsenella species in mice with experimental cancer, they isolated at least one chemical to explain how this happened.  Their discovery may advance cancer therapy and contribute to a better understanding of how the microbiome and our immune systems interact.

By looking at mice raised without any bacteria in their GI tract who were induced to have a specific cancer, they could compare their response to a specific cancer therapy based on whether or not they also received these bacteria.  The cancer therapy is a new type of immune therapy called checkpoint inhibitors which turn off the “off-switch” (i.e. double negative), greatly enhancing our body’s ability to attack caner cells.  For the mice who did not receive these bacteria, the checkpoint inhibitor had not effect.  For the mice who received the bacteria, the cancer shrank.

Their research pointed to a chemical called inosine which these particular bacteria make.  The inosine was found to activate T cells which were necessary to kill the tumor.  These T cells get their name from their development in our thymus gland and are critical cells in our immune system.  Absence of these cells is debilitating and leads to severe infections if not death from a variety of microbial invaders.  The inosine combined with the therapy was night and day different than the immunotherapy alone.

The researchers plan to continue studying how the bacteria and/or the inosine might be harnessed to treat human cancers.  For functional medicine practitioners, it underscores the critical role of our microbiome in immune health.  Promoting a healthy gut microbiome with fiber, probiotic foods, and a low inflammatory diet will benefit not only our digestion, but our immune defenses as well.  That is why functional medicine always focuses some attention to gut health as we work patients towards healthier, more abundant lives.


Original Article:

Lukas F. Mager, Regula Burkhard, Nicola Pett, Noah C. A. Cooke, Kirsty Brown, Hena Ramay, Seungil Paik, John Stagg, Ryan A. Groves, Marco Gallo, Ian A. Lewis, Markus B. Geuking, Kathy D. McCoy. Microbiome-derived inosine modulates response to checkpoint inhibitor immunotherapy. Science, 2020; eabc3421 DOI: 10.1126/science.abc3421

Thanks to Science Daily:

University of Calgary. “Researchers discover the microbiome’s role in attacking cancerous tumors.” ScienceDaily. ScienceDaily, 13 August 2020. <>.

Sanctuary Functional Medicine, under the direction of Dr Eric Potter, IFMCP MD, provides functional medicine services to Nashville, Middle Tennessee and beyond. We frequently treat patients from Kentucky, Alabama, Mississippi, Georgia, Ohio, Indiana, and more... offering the hope of healthier more abundant lives to those with chronic illness.

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