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Mediators of Inflammation
Volume 2007, Article ID 53805, 8 pages
Research Article

High Mobility Group Box 1 Protein Induction by Mycobacterium Bovis BCG

1Department of Medical Microbiology and Immunobiology, University of Szeged, Szeged 6720, Hungary
2Department of Medical Biology, University of Szeged, Szeged 6720, Hungary
3Proteomics Research Group, Biological Research Center of the Hungarian Academy of Sciences, Szeged 6720, Hungary
4Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
5Laboratory of Molecular Neurobiology, University of Helsinki, Helsinki 00014, Finland

Received 1 June 2007; Accepted 9 October 2007

Copyright © 2007 Péter Hofner et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


High mobility group box 1 protein (HMGB1), a nuclear protein, is a critical cytokine that mediates the response to infection, injury, and inflammation. The aim of our study was to elaborate a reliable in vitro model to investigate whether Mycobacterium bovis BCG is able to induce HMGB1 secretion from the monocytic U-937 cells. Western blot technique was applied for the detection of HMGB1 from supernatants of cells, following induction with Mycobacterium bovis BCG. Densitometric analysis revealed higher concentrations of HMGB1 in cell supernatants stimulated with BCG than in the supernatants of the control, nonstimulated cells. Further quantitation of the secreted HMGB1 was performed by ELISA. The BCG strain resulted in a higher amount of secreted HMGB1 (450 ± 44 ng/mL) than that of LPS (84 ± 12 ng/mL) or Staphylococcus aureus (150 ± 14 ng/mL). BCG and Phorbol 12-myristate 13 acetate (PMA), added together, resulted in the highest HMGB1 secretion (645 ± 125 ng/mL). The translocation of the HMGB1 towards the cytoplasm following infection of cells with BCG was demonstrated by immunofluorescence examinations. Conclusion: Our pilot experiments draw attention to the HMGB1 inducing ability of Mycobacterium bovis. Assesment of the pathophysiological role of this late cytokine in mycobacterial infections demands further in vitro and in vivo examinations.