…The latest techniques involve genetically engineering immune T-cells to target and kill cancer cells, while leaving healthy cells relatively unscathed.
T-cells normally travel around the body clearing sickly or infected cells. Cancer cells can sometimes escape their attention by activating receptors on their surface that tell T-cells not to attack…
[Researchers have engineered] T-cells to recognise markers that only cancer cells possess. What gives T-cells this potential, is that they can home in on what is going on inside cells, as well as outside. This vastly expands the range of potential targets.
Inside all cells, proteins are routinely broken apart and the resultant debris of tiny fragments called peptides are ferried to the cell surface by molecules called human leukocyte antigens (HLAs). These peptides then get inspected by passing T-cells – a process that allows the immune system to routinely check what is going on inside cells. If the peptide fragment looks normal, the T-cell gives the OK and moves on, but if it is abnormal, perhaps because of a viral invasion or cancer mutation, the T-cell will destroy the cell (see diagram). But sometimes, for unknown reasons, mutated cancer peptides are seen as healthy by T-cells and are ignored.
So now, researchers are reprogramming T-cells to respond specifically to peptides with hallmarks of cancer delivered to the surface from within cells.