We could improve the immune system’s memory when dealing with illnesses: Montreal study

We could possibly increase the effectiveness of the immune system against viruses and cancer, by enhancing the “memory” of certain cells, according to findings by the Montreal Clinical Research Institute.

This memory, which allows the immune system to recognize an enemy it fought already, is usually associated with T and B lymphocytes.

However, natural killer (NK) cells are also capable of remembering previous infections.

Dr. André Veillette and his colleagues demonstrated that the production of memory NK cells is controlled by a group of molecules called SLAM receptors.

We could consider stimulating SLAM with drugs such as antibodies to increase the number of memory NK cells, a strategy that could be useful for increasing protection against viruses and maybe cancers.

“One of the problems with cancer is that the immune system becomes a little dormant and it lets things through that it shouldn’t,” explained Dr. Veillette. “And then one of the treatments against cancer is to wake up the immune system with immunotherapy which will allow the system (…) to see the cancer, and then not only to get rid of it, but also to prevent it from coming back because there is an immune memory that has developed against the cancer.”

The field of immunotherapy is accelerating and is at the origin of the most promising breakthroughs made in the fight against cancer over the past 10 years.

“When you give immunotherapy, (…) the cells generated against the cancer will persist afterwards, so that if the cancer tries to come back, it will have more difficulty,” said Veillette. “It’s easier to understand with viruses (…), but cancer is the same thing: once you have developed an immune memory against cancer, the memory will persist.”

Using mice and one mouse equivalent to the cytomegalovirus virus, Dr. Veillette’s team demonstrated that SLAM receptors prevent the destruction of memory NK cells and increase protection against the virus.

However, when SLAM receptors are eliminated, Veillette claims that the memory of these cells disappears.

“The idea is that if we could stimulate the function of these receptors by antibodies, for example, or other types of drugs (…) we could also possibly increase immune memory mediated by NK cells, (obtain a) better cooperation with T and B lymphocytes, and then have better protection against viruses, but also perhaps against cancers,” explained Veillette.

He adds that this work highlights the “very great importance” of SLAM receptors in the control of immune functions, especially in the context where the scientific community is increasingly interested in the potential of memory NK cells ― by increasing their strength and number ― to fight cancer.

“There are clinical studies on this,” said Dr. Veillette. “So, I think that we, by using drugs that stimulate SLAM, potentially could increase the strength and number of memory NK cells. Increasing protection against infections is one thing, but I think that it is especially against cancers that it could have a therapeutic impact. That should be the next exploration we do.”

The findings of this study were published by the journal Cell Reports.

This report by La Presse Canadienne was translated by CityNews.