Cambridge researchers have discovered how T cells – an important component of our immune system – are able to keep killing while chasing and killing cancer cells, repeatedly reloading their toxic weapons.
Cytotoxic T cells are specialized white blood cells that are trained by our immune system to recognize and eliminate threats — including tumor cells and cells infected with invasive viruses, such as SARS-CoV-2, which cause COVID-19. They are also at the core of new immunotherapies that promise to transform cancer treatment.
Professor Gillian Griffiths of the Cambridge Institute for Medical Research, who led the research, said: “T cells are trained assassins who are sent on their deadly missions by the immune system. There are billions of them in our blood, each involved in a fierce and relentless struggle to keep us healthy.
“Once a T cell has found its target, it binds to it and releases its toxic load. But what is particularly remarkable is that they can then continue to kill and kill again. Only now, thanks to state -of-the-art technologies, we have been able to figure out how to reload their weapons. “
Today, in a study published in Science, the team has shown that refueling the toxic weapons of T cells is regulated by mitochondria. Mitochondria are often referred to as the batteries of a cell, as they provide the energy that drives their function. In this case, however, mitochondria use a completely different mechanism to ensure that the killing T cells have sufficient ‘ammunition’ to destroy their targets.
Professor Griffiths added: “These assassins must rebuild their toxic payload so that they can continue to kill without harming the T cells themselves. This careful balancing act proves to be regulated by the mitochondria of T cells, which set the rate of killing in according to how fast they can produce proteins themselves. This allows killer T cells to stay healthy and continue to kill under challenging conditions when a prolonged response is required. “
To accompany the study, Professor Griffiths and colleagues have released footage showing lethal T cells while hunting and eliminating cancer cells.
A teaspoon full of blood alone is thought to have about 5 million T cells, each measuring about 10 micrometers in length, about one-tenth the width of a human hair. The cells seen in the video as red or green amorphous ‘blobs’ move around quickly, examining their environment as they travel.
When a T cell finds an infected cell or, in the case of the film, a cancer cell, membrane protrusion rapidly examines the surface of the cell and checks for signs that this is an uninvited guest. The T cell binds to the cancer cell and injects toxic ‘cytotoxin’ proteins down special pathways called microtubules to the interface between the T cell and the cancer cell before puncturing the surface of the cancer cell and delivering its deadly load.
The body’s ‘serial killers’ caught on film destroying cancer cells
Miriam Lisci et al., Mitochondrial translation is required for sustained killing of cytotoxic T cells, Science (2021). DOI: 10.1126 / science.abe9977. www.science.org/doi/10.1126/science.abe9977
Provided by the University of Cambridge
Citation: Mito Warriors: Scientists Discover How T Cell Killers Reload Their Weapons to Kill and Kill Again (2021, October 14) Retrieved October 14, 2021 from https://medicalxpress.com/news/2021-10-mito- warriors-scientists-cell -assassins.html
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