Every day, the human body manufactures and destroys about 100 billion neutrophils- the most common type of white blood cell and one of the most highly-produced cells. Neutrophils live about eight hours, are bacteria-eaters and are a key component of the immune system. Without them, the body can be subject to life-threatening infection.
But how does the body keep the number of neutrophils produced constant in the blood, a mystery to scientists for decades? Researchers at the Cardiovascular Research Center at the University of Virginia Health System believe they have the answer.
They’ve discovered that these bacteria-killers in the blood are regulated by a sophisticated physiological process, much like the body’s blood pressure or water level. Their research is detailed in the March 23 issue of the journal Immunity.
Working with laboratory mice, Dr. Klaus Ley, professor of biomedical engineering at U.Va. and a U.Va. graduate student, Matthew Stark, discovered a new type of T lymphocyte, the cells that are the main means of providing the body with immune capability. This newly discovered cell, found in the lymph nodes of the gut, is called a Tn cell by Ley and Stark because it is responsible for regulating neutrophils.
“As far as we know, these primitive cells make mainly one cytokine, the protein produced primarily by white blood cells. This cytokine is IL-17,” Ley explained. “These cells are also under the control of another cytokine, IL-23. As the name suggests, these cells are responsible for regulating neutrophil numbers produced in the bone marrow. This finding will probably have significant impact not only for research, but also for clinical medicine.”