Natural Killer Cells to the Rescue

 
The nervous system reacts to dangerous stimuli by sending signals to the brain which it interprets as pain. The person then immediately reacts to protect itself.  Feelings of fear – stimulated by an approaching hungry lion let’s say – motivates us to run away as fast as we can, supported by rushes of adrenaline to help us run even faster.

The immune system is another remarkable facet of body’s defense systems. Inside our circulatory system is a range of cells that are programmed to battle dangerous invaders. Researchers often classify 3 forms of these cells. The first two are termed B-Cell and T-Cell Lymphocytes. The third form is termed “Natural Killer Cells” (or NK Cells).

First discovered in the early 1970s by Dr. Jerry Thornthwaite, NK Cells were determined to be a separate class of lymphocyte that do not need to be activated by an antigen or foreign body. The majority of lymphocytes or white blood-cell first need to be in close proximity with a foreign body or antigen to become activated – creating an antibody. These antibodies attack potentially dangerous foreign invaders, such as bacteria. The Natural Killer Cells, which represent only a small percentage of lymphocyte population, however do not need to be activated. The cells will attack a virus invader without the antigen-antibody activation, as Natural Killer Cells have the ability to differentiate between cells that are indigenous to the body versus those that are not.

Recent research conducted at Drexel University has now demonstrated the importance of Natural Killer Cells in controlling primary influenza virus infection. These findings may help us understand how the body's immune system may best respond to the newly emergent swine flu.

While no studies have been conducted on the specific H1N1 strain of influenza virus referred to as "swine flu," Drexel researchers have asked the question "How does the immune system respond the first time it encounters a new strain of influenza virus?"

Dr. Barry W. Ritz, Research Assistant Professor in the Department of Biology of Drexel University, and colleagues, worked with mouse models examining the activity of Natural Killer Cells in battling influenza. They were able to show that NK Cells do help control influenza virus early during an infection. Critically they were also able to demonstrate that NK cell function decreases with old age.

The study reported: "NK cells are among the earliest responders to influenza virus infection and help control the infection, and because NK cells are non-specific in their response to influenza virus infection, they respond similarly no matter the source of the infection."

Dr. Ritz and colleagues have also studied the importance of nutritional status and specific nutritional interventions to support NK Cell activity in response to influenza virus infection.

Dr. Ritz: "Certain nutritional interventions, or nutraceuticals, appear to have a positive effect on the NK cell response to influenza virus infection."

Researchers were clear though that they had not worked with the H1Ni strain and were wary of making any direct correlation between their work and the present influenza outbreak.