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Tweaking the body's serial killer - T Cells under the microscope

posted 23 Feb 2012, 06:33 by Mpelembe Admin   [ updated 23 Feb 2012, 06:34 ]

British scientists have produced a series of videos showing microscopic Cytotoxic 'killer' T cells destroying cancer cells in the human bloodstream. Their analysis of the T cell's remarkably efficient, destructive qualities aims to eventually improve the body's natural immunity against cancer and help overcome autoimmune diseases.

GRAPHICS  (ALEX RITTER/GILLIAN GRIFFITHS) - 
A team of Cambridge scientists believe their work on Cytotoxic 'killer' T cells could help improve the body's natural ability to destroy cancer cells and contribute to defeating a series of deadly autoimmune diseases.
Professor Gillian Griffiths leads the Wellcome Trust funded research team at the Cambridge Institute for Medical Research, producing a series of videos showing the microscopic killer cells destroying cancer cells.


Put together at 92 times normal speed the videos show the immune system cell on a mission to search for and destroy a tumour cell. According to Griffiths, the T cell's centrosome, shown in pink, hones in on a cancer cell and, with great precision, transfers toxic proteins that detroy the cancer.


"What you'll see is these little packages in pink focus towards the cancer cell, the killer T cell recognises him. Almost immediately it curls up, it rounds up and dies, it's an amazingly effective killer cell that's found in your bloodstream and what you'll notice now is that actually the killer cell, once it's killed, it can detect that and it moves off and it kills again and again and again. It's a serial killer."


Killer cells are some of the white blood cells in everyone's blood which defend our body against viral infections and cancer. They circulate around the body via the circulatory system and are able to squeeze through the walls of the blood vessels to hunt out cancerous and infected cells in the tissues throughout our body.


They are tiny - less than a tenth of the diameter of a strand of hair - and yet tremendously powerful, killing cancer cells, but leaving the surrounding healthy cells unharmed.


The team examined proteins within the blood and their molecular interactions in an attempt to piece together the steps that allow the killer cell to work properly. By looking at cells in which this process is interrupted - such as in the case of some genetic diseases - the team can work out the series of events required to allow killing to occur.


In some people killer cells contain genetic mutations, which disable them, making them unable to destroy targets.


These genetic mutations give rise to a range of primary immunodeficiencies, including lymphohistiocytosis, where excessive amounts of immune system proteins in the blood lead to fever, organ damage and, without treatment, death.


"There are some genetic conditions where children are born with mutations that mean that their T cells don't work properly and in this case there can be a variety of reasons as to why their killer cells can't deliver the packages, can't release the packages, and what we're trying to do is to find better ways to diagnose those patients quickly so they can be treated with bone marrow transplantation," explained Griffiths.


Research assistant Sam Grieve is examining protein mutations in the blood.

"Today I'm doing an experiment to see whether the mutations that we've found in the protein I'm looking at stop the interaction with another protein, and how this can stop the T cells killing," she explained.

Her colleague, PHD student Yvonne Hackmann, is undertaking similar work. Pointing to a high-speed video of a protein she said: "This is one of the proteins we work on that we found is important for a killer cell to kill a cancer cell and by solving the structure of this protein we can now see exactly where the human mutations are."


The team's work could help researchers identify ways to exploit our natural immunity to target cancer, as well as alleviate immune disorders where errant T cells destroy healthy tissue.


"What we're hoping with our research is that by understanding at the molecular level how these killer cells work that we can improve their ability to work against cancer more effectively and that we can also manage to turn them down when they're working inappropriately in autoimmune diseases," said Griffiths.

If the team is successful in its ambitious aims of making the population more resistant to cancer, the under-appreciated T Cell will surely takes its place as the most popular serial killer in history.

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