CHICAGO, March 20 (Xinhua) -- A study from Washington University School of Medicine in St. Louis suggests that the age of certain immune cells, called natural killer (NK) cells, used in immunotherapy plays a role in how effective the immunotherapy is.
Studying mouse and human induced pluripotent stem cells that have been coaxed into forming these unique NK cells, the researchers found that NK cells are better at releasing specific anti-tumor chemicals, a process called degranulation, than their adult counterparts.
Unlike the adult versions of NK cells used in most investigational therapies, earlier versions of such cells do not originate from bone marrow. Rather, these NK cells are a special type of short-lived immune cell that forms in the yolk sac of the early mammalian embryo.
"Now we know where these special natural killer cells come from and that we can never get them from an adult donor, only a pluripotent stem cell," said senior author Christopher M. Sturgeon, an assistant professor of medicine. "Based on their unique behavior alone, there is one small clinical trial of these cells that is ongoing. Now that we know how to manufacture them and how they work, it opens the door for more trials and for improving upon their function."
For therapeutic purposes, such cells do not need to originate from embryos, they can be developed from human pluripotent stem cells, which have the ability to give rise to many different cell types, including these specialized natural killer cells.
In general, NK cells do not heavily attack the body's healthy tissues, as many T cell therapies can. Even when NK cells do cause harm, they do not stay in the body for long periods of time.
The study was published on Thursday in the journal Developmental Cell.