By comparing the immune responses of both, young and old mice, to bacterial infection they found that the number of macrophages, one of the major cell populations involved in the elimination of infecting bacteria, decreases rapidly in aged mice. This decline in the number of fighters and the associated weakness of the immune defense may be responsible for the age-associated increase in susceptibility to infections. The HZI researchers have succeeded to enhance the resistance to an infection in aged mice by treating them with a macrophage-specific growth factor. This treatment increases the amount of macrophages in aged mice and improves their capacity to fight the infection. This study has been published in the current issue of the scientific magazine "Journal of Pathology".
The main task of the immune system is to protect the body against invading pathogens. For this purpose, a variety of different cell types and molecular factors work together in a complex network. Together, they compose a highly effective defense front line. As we are getting older, our immune system changes: infections are more frequent and more severe, some immune cell types lose certain properties and their functionality declines – in short: the immune system grows old. "Since the immune system protects our body against infections, to keep the immune system young and functional is a crucial factor for a healthy aging," says Eva Medina, head of the HZI research group "Infection Immunology".
While many elderly people die from infections there's more riding on immune system rejuvenation than just infection fighting. There's a bell-shaped distribution between people in immune system ability to attack cancer and the ability of the immune system to fight cancer declines with age. Immune system rejuvenation might cause a large decline in the incidence of diagnosed cancer as youthful immune systems will some day probably kill off many cancers at early stages of development.
|Share |||Randall Parker, 2010 January 27 12:36 AM Aging Immune System|