The saying goes when things get tough, take a deep breath. While this relaxation technique protects our health, apparently it also improves our immune system functions. Scientists discovered a new protein that increases the respiration of CD8 cytotoxic T cells, making them more fit to fight chronic infections and cancer.
CD8+ T cells are an integral part of the immune system. Their job is to kill cells that have been transformed, either because of a viral infection or cancer. When CD8+ T cells encounter infected or cancer cells, they divide massively and kill the corrupted cells, limiting the spread of the disease. Once all is clear, most of the cells die, leaving behind what is called “memory” CD8 T cells. From their name, memory CD8 T cells remember the virus or cancer and are ready to kill again if they re-encounter it.
So, if we have such a strong immune player in place, why do chronic viruses, such as HIV or Hepatitis, and cancer cells can still take over our bodies? Because in such incidents, the high viral or cancer load results in “exhausted” CD8 T cells. With the constant stimulation, they stop responding properly and thus let infections and cancer go unchecked.1
There have been multiple attempts to determine how to make super-fit CD8+ T cells that can overcome getting exhausted. In a recent study that was published in Science magazine, researchers discover an orphan protein that can give CD8+ T cells such a boost. This newly discovered protein, which the scientists named lymphocyte expansion molecule, or LEM, increased CD8+ T cell proliferation, function, and memory development in response to chronic viral infections and tumors. The researchers also found that LEM is a part of a complex that is responsible for respiration in the mitochondria, the powerhouse of the cell. The LEM protein increased the respiratory levels in CD8+ T cells, making them divide more efficiently and rapidly, thus exhibiting a better capacity to kill ailing cells. 2
This discovery opens a new frontier in the ability to restore the proliferative function of CD8+ T cells by adjusting oxidative respiration. By manipulating the LEM protein, scientists can improve CD8+ T cells responses during chronic viral infection and/or cancer. Here at HemaCare, we provide CD8+ T cells from both healthy and chronically infected individuals that can be used to study the role of respiration in augmenting their function. We are very excited about this new discovery and we look forward to following upon the future of modulating respiration as a new therapy against viral infections and cancer.
1 Speiser et al. (2014). T cell differentiation in chronic infections and cancer: functional adaptation or exhaustion? Nature Reviews Immunology 14. Doi:10.1038/nri3740.
2 Okoye et al. (2015). T cell metabolism. The protein LEM promotes CD8 T cell immunity through effects on mitochondrial respiration. Science 348 (6238). Doi:10.1126/science.aaa7516.