Microbiology

At the Point of Attack

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Science  23 Mar 2007:
Vol. 315, Issue 5819, pp. 1638
DOI: 10.1126/science.315.5819.1638c

Tuberculosis kills approximately 3 million people each year. The pathogenic agent Mycobacterium tuberculosis invades and replicates within macrophages, constructing for itself an intracellular vacuole that shelters it from immune surveillance and attack. Alteri et al. have investigated how M. tuberculosis binds to and invades potential host cells. On the surface of the microbe, they discovered fine fibers, referred to as pili, that are 2 to 3 nm wide and are likely to be important in enabling the microbe to adhere to target cells. They isolated the pili and have characterized their composition using mass spectrometry and immunochemistry. The pili are assembled from low-molecular-weight protein subunits; these bind to the protein laminin, which is an abundant component of the extracellular matrix within human tissues. Furthermore, the sera of tuberculosis patients contained antibodies that recognized the pilin subunit. The unanticipated identification of what may represent a key protein in the early stages of host colonization by M. tuberculosis may lead to the development of new therapies and vaccines. — SMH

Proc. Natl. Acad. Sci. U.S.A. 104, 5145 (2007).

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