T cells burn out just a few hours after encountering cancer tumors

A key function of our immune system is to detect and eliminate foreign pathogens such as bacteria and viruses. Immune cells like T cells do this by distinguishing between different types of proteins within cells, which allows them to detect the presence of infection or disease.

A type of T cell called cytotoxic T cells can recognize the mutated proteins on cancer cells and should therefore be able to kill them. However, in most patients, cancer cells grow unchecked despite the presence of T cells.

The current explanation scientists have as to why T cells fail to eliminate cancer cells is because they become “exhausted.” The idea is that T cells initially function well when they first face off against cancer cells, but gradually lose their ability to kill the cancer cells after repeated encounters.