June 13, 2012 Researchers have identified the primary player of
the biochemical bugle call that musters the body's defenders
against viral infection. Scientists at Washington University
School of Medicine in St. Louis have shown that a key molecule,
MDA5, is essential for producing enough interferon (the bugle
call) to rally virus-fighting cells during certain viral
infections. In mice, the lack of MDA5 forces the immune system
to rely on less effective defenders, which may give the virus
opportunities to establish or expand a chronic infection. Like
the cavalry charge in classic movies, timing is critical in
fighting a viral infection. If a surge of interferon comes early
enough, the immune system can limit or clear a virus. If the
boost is too late, though, the defenses may already be
overwhelmed. "If an injection of interferon is given within a
certain time frame in the infectious process, we found that it
was possible to decrease viral spread and bolster antiviral CD8
T cell responses in our mouse model,"