New research may have discovered a new culprit that helps tuberculosis evade the immune system: stem cells.
Human lung granuloma from TB patient
Image: Wikimedia Commons/Mutleysmith
The research, conducted largely in vitro using mouse cells and linkurl:reported; in __PNAS__, suggests that stem cells recruited to sites of tuberculosis infection may suppress surrounding immune cells, thereby helping the bacterium establish a persistent infection."It's a novel finding," added linkurl:Joanne Flynn,; an immunologist at the University of Pittsburgh School of Medicine, who was not involved in the study. About one third of the human population carries __Mycobacterium tuberculosis__, but only around 10 percent of those infected go on to develop the often deadly pulmonary disease. In these individuals, actively replicating bacteria in the lungs and other organs encounter a slew of macrophages, epithelioid cells, and lymphocytes, which surround the bacteria and form a sphere of tightly bound cells known as granulomas. Unable to...
S. Raghuvanshi et al., "__Mycobacterium tuberculosis__ evades host immunity by recruiting mesenchymal stem cells," PNAS, doi:10.1073/pnas.1007967107, 2010.

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