T-Cell Immunotherapy Could become a Vaccine-like Cancer Preventative
Clinicians treating cancer face many challenges. They must ensure that therapies do not cause more harm than benefit, which is an especially difficult task in children. Optimal treatment conditions are to catch the cancer early, target only diseased cells, and have minimal side effects. This may sound like an improbable wish list, but new research into modified T-cells may indeed offer a treatment that meets all these requirements. Researchers are using the science of immunotherapy and targeted T-cells to detect and destroy cancer cells without harming normal tissue.
The immune system polices the body in order to seek out and destroy infections or harmful cell mutations. However, tumors produce signals which ‘turn off’ the immune system’s ability to recognize diseased cells. Immunotherapy counteracts this mechanism by creating modified T-cells which actively seek out cancer cells.
T-cells are often described as the workhorse of the immune system because they tirelessly patrol the body’s tissues on the lookout for infection or disease. This new research uses modified T-cells programmed to zero in on certain peptides found on the surface of cancer cells. The T-cells travel through the vasculature to the source of the signal and then destroy the tumor cells. One of the major benefits is the peptides are cancer-specific, so T-cells ignore healthy cells—an obvious advantage over current chemotherapy agents.
Scientists dub these modified T-cells as a ‘living drug’. Unlike a pharmaceutical, which needs repeat doses, a single dose of T-cells has the ability to reproduce and pass on their memory of cancer peptides to the next generation. The implication is that a single infusion of modified T-cell could self-perpetuate and police the body for the duration of that patient’s lifetime. This also prevents the metastatic spread of tumors, since the T-cells could also recognize and destroy individual cells.
So far, modified T-cells have been programmed to fight cancerous B-cells in the bloodstream. One long-term trial gave ten patients bone marrow transplants of modified T-cells. After 14 years later, researchers were still able to detect the modified T-cells in their circulation which leads them to believe that these cells were still playing an active role in surveillance for cancer cells.
The implications for this treatment for blood-borne cancers is immense. T-cell modification prevents cancers from concealing themselves from the immune system and promotes active destruction of cancer cells. It also facilitates continuous surveillance of the body, meaning a cancer could be found and destroyed far in advance of any routine screening program. The treatment offers lifelong protection that is not dependent on medications or drugs which could harm healthy tissue.
So far T-cell immunotherapy has only been used to target blood-borne cancers, but the possibilities for treating other cancers are extremely exciting. There is ongoing research of applying this technique to gynecological cancers such as ovarian cancer, which are often detected at an advanced stage and with reduced rates of treatment success. The possibility of using modified T-cells as a form of vaccination to seek out these cancers at its earliest stage would indeed be a life-changing step forward for preventative medicine.