Health Watch -- Killer Cells

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Understanding how the body gets rid of unwanted invaders may lead to better treatments for cancer and other diseases.

The human body has its own defense system -- specialized cells that attack and destroy invaders such as viruses and cancer cells. Researchers at UT Southwestern Medical Center at Dallas have learned more about how these cells work, and this knowledge may aid in the development of treatments that will help these cells function more effectively.

There are two key kinds of immune cells, natural killer - or NK - cells and cytotoxic T cells. The researchers used 3-D microscopes to observe in real time as these cells attacked target tumor cells in a laboratory setting. They found that the cells have a defined series of steps they go through in killing tumor cells. Both kinds of cells release toxic molecules as they attack, but they do so in different ways. The NK cells are the first line of defense, attacking infections and tumors. The cytotoxic T cells are the second wave and are more thorough. They retain a sort of memory of past invaders and will respond vigorously if the same infection or tumor returns.

The researchers focused on the cells' cytoskeletons, which organize the structure of the cells' components. Dr. Christoph Wuelfing, the UT Southwestern immunologist who was the study's lead author, says that understanding how the cytoskeleton of NK cells is regulated could help scientists develop more powerful NK cells that will be better at fighting cancer.