Shedding Light on Tuberculosis Susceptibility

Science's STKE  28 Mar 2006:
Vol. 2006, Issue 328, pp. tw110
DOI: 10.1126/stke.3282006tw110

Since the late 1800s, sunlight and other forms of light therapy have been considered potentially beneficial for tuberculosis, most likely because of the antimicrobial effects of sunlight-induced synthesis of vitamin D. Liu et al. reveal that vitamin D signaling contributes to the Toll-like receptor (TLR) pathway of microbicidal defense to Mycobacterium tuberculosis (MTB) in monocytes and macrophages. Activation of the TLR2 and TLR1 heterodimer (TLR2/1) by a bacterial lipoprotein led to vitamin D receptor expression and processing of the pro-vitamin D precursor, which stimulated vitamin D-induced up-regulation of an antimicrobial peptide and killing of MTB bacilli. The low levels of circulating pro-vitamin D3 hormone and limited ability to induce the microbicidal peptide observed in sera of African American individuals may contribute to their increased susceptibility to tuberculosis.

P. T. Liu, S. Stenger, H. Li, L. Wenzel, B. H. Tan, S. R. Krutzik, M. T. Ochoa, J. Schauber, K. Wu, C. Meinken, D. L. Kamen, M. Wagner, R. Bals, A. Steinmeyer, U. Zügel, R. L. Gallo, D. Eisenberg, M. Hewison, B. W. Hollis, J. S. Adams, B. R. Bloom, R. L. Modlin, Toll-like receptor triggering of a vitamin D-mediated human antimicrobial response. Science 311, 1770-1773 (2006). [Abstract] [Full Text]