July 26, 2013 — As part of the innate immune system natural killer cells (NK cells) play an important role in immune responses. For a long time they have been known as the first line of defense in the fight against infectious diseases. Therefore, researchers assumed that the body needs as many active NK cells as possible. However, scientists at the Helmholtz Centre for Infection Research (HZI) have now shown that the principle "the more the better" does not apply to this type of immune cells.
"During certain phases of the immune response it seems to be beneficial to have less active natural killer cells," says Dr Jadwiga Jablonska-Koch, member of the research group "Molecular Immunology" at the HZI and responsible author of a new study published in the European Journal of Immunology. "This is particularly true during the beginning stages of an infection, which is precisely when they were assumed to be most important."
Usually, Listeria monocytogenes infection leads to a deadly sepsis in mice and immune suppressed humans. Interestingly, researchers observed that removal of NK cells during the early stages of Listeria monocytogenes infection improves survival of the mice. These new findings could help to prevent sepsis in the future.
Until now it was believed that mice and humans die from listeriosis because their killer cells do not fight the infection effectively enough. However, the new results show the exact opposite. Even though the killer cells produce messenger substances that activate the immune system, the overproduction of the interferon IFN-
"During certain phases of the immune response it seems to be beneficial to have less active natural killer cells," says Dr Jadwiga Jablonska-Koch, member of the research group "Molecular Immunology" at the HZI and responsible author of a new study published in the European Journal of Immunology. "This is particularly true during the beginning stages of an infection, which is precisely when they were assumed to be most important."
Usually, Listeria monocytogenes infection leads to a deadly sepsis in mice and immune suppressed humans. Interestingly, researchers observed that removal of NK cells during the early stages of Listeria monocytogenes infection improves survival of the mice. These new findings could help to prevent sepsis in the future.
Until now it was believed that mice and humans die from listeriosis because their killer cells do not fight the infection effectively enough. However, the new results show the exact opposite. Even though the killer cells produce messenger substances that activate the immune system, the overproduction of the interferon IFN-