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Developing a fever gives the immune system a boost, according to a study in the December 2006 issue of Nature Immunology.
Sharon Evans and colleagues show elevating the internal temperature in mice, mimicking the fever response to infection, increases the number of immune cells that are recruited to the lymph nodes where these cells are educated and armed to seek out and destroy the offending pathogen. Lymph nodes act as the powerhouse of the immune system. Cells and particles from nearby tissues drain into lymph nodes and alert lymphocytes, immune cells that enter nodes via the bloodstream, to the presence of foreign intruders. Evans’ group reports that fever acts on cells called ‘high endothelial venule cells’ (HEVs), which function as gatekeepers between blood-borne cells and lymph nodes. Fever triggers HEVs to produce more CCL21, a molecule that recruits lymphocytes to the lymph node from the blood. Fever also increases the number of adhesion molecules on the surface of HEVs, resulting in more efficient lymphocyte entry into the nodes. Indeed, lymph nodes swollen by increased numbers of immune cells, as seen with mumps disease, are commonly recognized as a sign of infection. So when suffering with a cold if you consider reaching drugs to reduce your temperature, remember that fever can actually be good for you. Author contact: Sharon S Evans (Roswell Park Cancer Institute, Buffalo, NY, USA)
E-mail: sharon.evans@roswellpark.org For additional comment on the paper: Andrew D Luster (Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, USA)
E-mail: luster@helix.mgh.harvard.edu Abstract available online. (C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza
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