Bacteria Can Induce A Harmful Immune Response

Main Category: Immune System / Vaccines
Also Included In: Infectious Diseases / Bacteria / Viruses
Article Date: 17 Jun 2009 - 3:00 PDT

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Molecules known as type I IFNs are a central component of the protective immune response following infection with a virus. In contrast, these molecules are not normally linked to the protective immune response following infection with the bacterium Staphylococcus aureus, which is becoming a major health problem due to the emergence of methicillin-resistant (MRSA) strains. However, Alice Prince and colleagues have now determined that Staphylococcus aureus induce the production of type I IFNs by mouse and human airway cells, but these molecules are not part of a protective immune response in mice, rather they markedly enhance the severity of the pneumonia caused by Staphylococcus aureus infection.

In the study, the researchers were able to pin down the Staphylococcus aureus protein that causes mouse and human airway cells to produce type I IFNs, protein A. Further analysis identified the region of protein A responsible, the Xr domain, and determined the importance of the type I IFNs produced - mice lacking the molecule to which most type I IFNs bind were dramatically protected from lethal pneumonia caused by infection with Staphylococcus aureus. As the signaling pathway by which type I IFNs activate their effects is very well defined, the authors suggest that targeting molecules in this pathway might provide a beneficial therapeutic approach for treating pneumonia caused by Staphylococcus aureus infection.

TITLE: Staphylococcus aureus activates type I IFN signaling in mice and humans through the Xr repeated sequences of protein A

AUTHOR:
Alice Prince
Columbia University College of Physicians and Surgeons, New York, New York, USA.

View the PDF of this article at: https://www.the-jci.org/article.php?id=35879

Source:
Karen Honey
Journal of Clinical Investigation
JCI online early table of contents: June 15, 2009