Training The Immune System To Attack Cancer With Probiotics

Novel Immunotherapy

Most modern cancer therapies aim to train the body’s immune system to detect and attack cancer cells efficiently. This method even won the 2018 Nobel Prize in Medicine (see the link for more information).

It can be done with now-established therapies like CAR-T therapies or maybe soon experimental treatments like mRNA vaccines against specific cancers, which are making quick progress with clinical trials for mRNA against lung cancer.

However, this is not the only possible way to encourage the immune system to target cancer cells. Researchers at Columbia University, New York, have modified bacteria to attack cancer. They published their findings in the prestigious publication Nature under the title “Probiotic neoantigen delivery vectors for precision cancer immunotherapy.”

Using Bacteria Against Cancer

The idea is not new; in the 19th century, it was noticed that injecting bacteria into a tumor could cause it to shrink. Today, early-stage bladder cancers are treated with bacteria. The mechanism behind it is that bacteria can prosper in the oxygen-deprived environment of tumors and locally provoke an immune response that attacks both the bacteria and the cancer cells.

The issue is that such an undirected process is often not enough to help with cancer therapy. So, the bacteria have to be modified for maximum efficiency.

Customizing Bacteria For Cancer Detection

The central concept is to make the bacteria express markers specific to cancer cells. These “neoantigens” are proteins that cancer cells produce but normal cells do not.

By having the bacteria carrying these proteins, the immune systems detect them and start attacking anything carrying them, both bacteria and cancer cells.

This has a solid advantage over the type of immunotherapy, as the bacteria-induced reactions activate a wide variety of different immune cells. So it involves NK cells, lymphocytes CD4+ and CD8+, macrophages, antigen-presenting cells (APC), etc.

Reducing Immunity Suppression