How do our bodies know when a virus is lurking about? In the December issue of Nature Immunology, Trinchieri and colleagues at the Schering-Plough Research Institute in Dardilly, France, report the identity in mice of a specialized immune surveillance cell that specifically responds to the presence of viruses by rapidly releasing massive amounts of interferon-alpha, which induces an anti-viral state throughout the individual.
Consider our attention to the upcoming flu season as an example of the importance of generating anti-viral responses. Trinchieri shows that interferon-alpha-producing cells (IPCs), which were identified earlier in humans and now also shown here in mice, resemble immature dendritic cells. However, they must have some non-obvious specializations, as these cells do not respond to bacterial stimuli and differ in expression of surface proteins that may distinguish both their localization within tissues and, presumably, their function in the body. These IPCs are the major producers of interferon-alpha, which plays a crucial role in limiting early virus spread and activates cellular mechanisms that, as the name implies, interfere with viral replication. Finally identifying this cell in mice provides us with a system in which to test for the optimal means of inducing IPCs when needed.
Schering-Plough Research Institute
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Additional contact for comment on paper:
David F. Tough
The Edward Jenner Cancer Institute
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Message posted by: Trevor M. D'Souza