By Xinyi NanImagine one day in the future, not too long from now, where each cancer patient can be given a personalised set of treatments specifically targeted at one’s unique cancer cells, thus resulting in efficient tumour regression and fast recover rate. This is where the current development of immunotherapy using genetically modified T cells is leading to.
Immunotherapy is a type of disease treatment relying on the fact that the human immune system is able to recognise pathogens and elicit immune response to protect our body against these unwanted intruders. An easy way to understand this is to think about the common vaccination we receive. T-lymphocytes, or T cells, are an important group of white blood cells that forms part of this immune system, which when activated would initiate both humoral and cell-mediated immune response. But all this is based on the activation of the T cell through a protein called the T-cell receptor (TCR), found on the cell surface. And this TCR is what scientists are focusing on.
In the case of cancer, the activation sources of the T cells are tumour antigens. With recent advance in genetic engineering, scientists are able to modify the T-cell receptors so that it can recognise and increase their affinity for certain tumour antigens, transfer them into T-cells and hence allow them to be activated upon encountering the target antigens in patients. These antigen-specific receptors can either be naturally occurring ones isolated from some patients, or the chimeric antigen receptors (CARs) which are artificially engineered receptors often derived from antibodies. These receptors are then transferred into T cells through gene transfer vectors, which in turn are introduced into the patients’ lymphocytes. Figure 1 shows the general schema of how the above process works.