Basic research into the dual nature of certain immune system cells has set the stage for a new approach to cancer immunotherapy that avoids some of the shortcoming associated with other methods.
The new approach incites an immune system attack on tumors by changing the very identity of key immune system cells dispersed throughout the tumor. T regulatory cells ordinarily prevent their more combative cousins known as T effector cells from attacking the tumor.
Researchers showed the eliminating a key protein in T regulatory cells makes those cells so unstable that they become T effector cell and join in the destruction of the tumor.
Researchers we also able to how that conversion from T regulatory to T effector occurs only in the inflammatory conditions that prevail within many tumors. As a result, T regulator cells embedded in normal tissue throughout the body continue to have a restraining effect on their local T effector cells protecting healthy organs and tissues from attack.
These findings make researchers hopeful about the prospects of therapies that concentrate the immune system’s firepower on tumors without producing residual damage and harmful side effects.
Current approaches to immunotherapy involve depleting or blocking T regulatory cells in order to shift toward T effector cells. However, this method runs the risk of triggering an autoimmune response in which the T effector cells attack normal as well as malignant tissue.
The key to this new approach is that it singles out the T regulatory cells inside a tumor for conversion, leaving the T regulatory cells elsewhere in the body unchanged.
This study builds on previous research that reported that T regulatory cells maintain their immune-suppressive properties under inflammatory conditions as long as they have high enough levels of protein called Helios. The research also found that depriving them of sufficient Helios caused them to lose that stability and turn into T regulatory cells.
This represents a next stage in cancer immunotherapy. The next step is to organize a clinical trial using this approach in patient.