Sunday, 29 December 2019
A Belgian researcher has made important steps in developing a new technique that would recruit the body’s own defences against the presence of cancer cells.
Ultimately, the technique would be much less damaging than conventional techniques such as radio- and chemotherapy.
Sophie Lucas is a researcher at the Duve Institute, linked with the Catholic University of Louvain-la-Neuve (UCL). Her work concerns a type of cell known as Regulatory T lymphocytes, or Tregs – cells that are part of the lymph system which makes up a large part of the body’s immune system.
Some reactions of the immune system can cause auto-immune conditions, where the body’s defences attack healthy tissues, causing numerous conditions including Type 1 diabetes, lupus, psoriasis and coeliac disease. Even simple hay fever is a sort of auto-immune condition, where the body has a violent reaction to something which is not in itself dangerous, i.e. tree or grass pollen.
The body has equipped itself with Treg cells to suppress excessive immune reactions, but these cause a problem in the case of cancer. “In cancer patients, they may favour tumour progression by suppressing immune responses against tumour cells: Tregs inhibit anti-tumour T cells, “Lucas writes on the Institute’s website. “Our group studies how human Tregs inhibit anti-tumour responses.”
Cancer itself can be seen as a consequence of the inhibitory action of Tregs. When cancer cells begin to grow in the body, the immune system attacks them as foreign bodies. But as the cancer grows large enough to be detectable, the immune system is not able to keep up with its growth, and this is one probably result of Treg action: the Tregs have stopped the immune system from working full-out.
The idea is to somehow harness the power of Tregs to turn them against not the body’s own immune response, but the presence of the cancerous cells themselves. The Tregs and the body’s normal immune system would then work together against the invader, instead of being in opposition to each other.
The Institute’s work is firstly to study how Tregs work, to allow researchers to develop ways of making them work as desired. But while Tregs can be difficult to differentiate from ordinary white blood cells, the team has found a work-around: “We circumvented this problem by deriving clones of human Treg cells. Clones are pure populations of cells that can be kept in culture for long periods of time, and provide very stable material to perform repeated experiments and derive robust results. We used our human Treg clones to identify functional features present in Tregs, but not in other types of lymphocytes, that could therefore mediate the Treg immune suppressive functions,” Lucas writes.
So far, the team has found that Tregs produce a protein called TGF-ß, which has an important role in immune system suppression. They regulate TGF-ß by using another protein attached to their surface, known as GARP. Now, if the exact roles of the two proteins separately and apart can be decoded, the possibility of ordering Tregs to stand down when the immune system is fighting cancer cells but not other malign cells, the battle against cancer could enter a new era.
“In the long term, the objective is to try to manipulate immune responses to make them more effective, and to permit the patient to reject their own tumour cells.”
The Brussels Times