Natural Born Killers: NK Cells Drafted Into the Cancer Fight

Extract

Once thought of as foot soldiers in the body’s fight against cancer, natural killer (NK) cells are more akin to special forces in bolstering the immune system to respond to foreign invaders. New studies are revealing that rather than randomly killing cells—as was thought for many years—NK cells are programmed to seek out specific targets on cancer cells.

“For the past 25 years, we have been so preoccupied with understanding B and T cells. We thought the other cells were nonspecific,” said Lewis Lanier, Ph.D., professor of microbiology and immunology at the University of California at San Francisco. “That was extremely naive and an oversimplification. ... We are finding out natural killer cells are not so nonspecific, but quite sophisticated.”

The immune system is made up of a series of highly choreographed white blood cells that interact with each other to mount an attack against invaders, such as viruses and tumors. B cells secrete antibodies or proteins that recognize and attach to foreign substances, such as a virus or bacterium, or antigens on cancer cells. Each type of B cell makes one specific antibody that attaches to one specific antigen, marking it for destruction by other immune cells. T cells directly attack infected, foreign, or cancerous cells. They too have to recognize a specific antigen before attacking.