In a paper in Nature Immunology, researchers from the Walter and Eliza Hall Institute and the University of Melbourne redefine how killer immune cells are mobilised in the body’s response to infections or cancer cells.
The discovery of how two pathways cooperate to unleash the immune system’s assassins, called cytotoxic or ‘killer’ T cells, could be harnessed in the future to improve the treatment of chronic infections or cancer.
Killer T cells detect, attack and kill abnormal cells in our body, such as cells that are infected with viruses or have undergone cancerous changes.
The formation of killer T cells is guided by signals, called cytokines, released by other immune cells. These signals are transmitted to two separate regulator proteins within the T cell, called Blimp-1 and T-bet. And while it has been known that these molecules both contribute to the formation of killer T cells, it was unclear how they work together.
Dr Annie Xin, Dr Axel Kallies (lead authors) and co-workers show that a combination of both signals triggers the formation of killer cells that can fight a viral infection. If one of these signals is lost, the immune response is dampened but still functional.
This creates a buffered system that helps the organism to fight different types of infections or cancerous cells, while avoiding damaging attack on healthy cells.
CD8 killer T cells are central to the recent breakthroughs in cancer immunotherapy, an extremely successful new approach to cancer treatment that harnesses the immune system to rid the body of cancer cells.