Scientists have discovered a molecule that helps activated immune cells survive in the face of massive amounts of the antimicrobial signalling protein, interferon-gamma. A paper online in Nature Immunology suggests the molecule Irgm1 is critical to allow continued immune responses in the face of chronic infections, such as those seen in many parasitic diseases.
Interferons are antimicrobial compounds that help eradicate viruses and other intracellular pathogens. High concentrations of interferons are toxic to nearby cells. Hence it has always been a dilemma as to how those immune cells that make interferon-gamma in response to infection can themselves survive.
Carl Feng and colleagues identify a molecule called Irgm1 that plays a key role in this process -- protecting immune cells that produce interferon-gamma from succumbing to its toxic effects. They show that immune cells from mice lacking Irgm1 fail to multiply and instead undergo a form of cellular suicide upon exposure to interferon-gamma. Fewer immune cells result in uncontrolled infections and all of the mice died from their infection. Mice lacking both Irgm1 and interferon-gamma survive infection, showing that Irgm1 protects these immune cells from the toxic effects of interferon-gamma.
Carl Feng (National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA)
Abstract available online.
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza