Our intestines have specialized cells that promote immune responses to various stimuli in their environment, according to a new report in the July 2005 issue of Nature Immunology. This finding could have implications for the development of effective oral vaccines, for which a strong immune response is desired, as well as for the treatment of inflammatory bowel diseases, such as Crohn's disease, for which dampening of inflammation is important. Currently around 600,000 Americans have some form of inflammatory bowel disease every year.
Conventional wisdom suggests that the gut favors a 'mild' local environment because it is necessary for us to live in harmony with a community of beneficial bacteria. However, the gut does respond to harmful bacteria and sometimes to harmless bacteria to cause inflammation. Manjunath and colleagues found that certain cells that produce a molecule called CD70 and reside in a region known as the lamina propria, which is just under the surface of the intestine. These CD70-producing cells are critical for expanding the number of immune T cells during an infection. The cells also help to further equip these T cells with offensive potentials.
Although the precise identity of the CD70-producing cells is still elusive, it is clear that the CD70 molecule is crucial in inducing a heightened immune response. Thus, targeting CD70 and its interacting partner on T cells provides the basis for further investigation into the control of gut immunity.
N. Manjunath (Harvard Medical School, Boston, MA, USA)
Additional contact for comments on paper:
Brian L. Kelsall (National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA)
Also published online(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza