Discovered: How do germs fight immunity

October 18th, 2008 - 1:37 pm ICT by IANS  

Washington, Oct 18 (IANS) Researchers have uncovered the mechanism of how viral infections block output of immune system proteins that protect one from diseases like HIV, TB and measles. These kind of proteins are known as type-I interferons, whose weakening lead to other, potentially deadly infections. The research, based on mice, point to potential new ways to treat immunosuppressive diseases.

“It’s the first demonstration that a virus causes suppression of the interferon response,” said the paper’s co-author Michael Oldstone, a Scripps Research Institute (SRI) professor and a pioneer in immune system studies.

“This model explains how a secondary infection can be caused by a normal virus infection and this provides the guide for what to do and where to look in human diseases, which are of course more difficult,” he added.

Mammals have two main ways to fight off infections. Adaptive immune responses are those that involve the production of antibodies and T lymphocytes that attack specific infections.

Conversely, innate immune responses are genetically encoded and are generally the same regardless of infection type. One of its key component is interferon, which plays a range of roles including direct antiviral effects, activating innate natural killer cells and adaptive T-lymphocytes, which destroy a wide range of infectious invaders.

To better understand this system, the Scripps Research team headed by Elina Zuniga worked with virus infected mice, for understanding immune system recognition of foreign substances like microbes and viruses. Their work was reported in the October issue of the journal Cell Host & Microbe.

The researchers found that the virus suppressed the mouse immune system by interacting with immune cells known as plamacytoid dendritic cells, which are key producers of one of two critical groups of interferons, known as type I.

Work could aid development of new treatments for such conditions as HIV, measles, and TB, according to a press release of SRI.

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