Every day, inside our body, there is a war going on. Microscopic invaders of one kind or another try to make a meal of us, and our immune system fights back, seeking out the invaders and destroying them. One of our body's most important foot-soldiers in this war is the T cell, a type of white blood cell with receptors that can recognize foreign substances. Like all white blood cells, T cells originate in the bone marrow, but then they migrate to an organ called the thymus (hence the "T" in "T cell"), where they evolve into specialized immune system warriors. Mature T cells, which leave the thymus and circulate around the body, come in different types. One type, the cytotoxic T cell, specializes in attacking and killing cells of the body that are infected by viruses, bacteria, or cancer.
Which is where this fascinating little video comes in. It shows a cytotoxic T cell (also known as a "killer T cell") attacking a cancerous cell. The process is shown at 92 times the actual speed. And for a sense of scale, a cytotoxic T cell is only 10 microns long, or about one-tenth the width of a human hair. The video was created by PhD student Alex Ritter at the University of Cambridge, and posted recently in the university's "Under the Microscope" Web series. Ritter's supervisor in the Department of Medicine, Professor Gillian Griffiths, explains the importance of the research associated with the video:
Cytotoxic T cells are very precise and efficient killers. They are able to destroy infected or cancerous cells, without destroying healthy cells surrounding them....By understanding how this works, we can develop ways to control killer cells. This will allow us to find ways to improve cancer therapies, and ameliorate autoimmune diseases caused when killer cells run amok and attack healthy cells in our bodies.