Hat-tip: Flutrackers.com
October 19, 2013
CAMBRIDGE, Mass. – Revealing influenza’s truly insidious nature,
Whitehead Institute scientists have discovered that the virus is able to
infect its host by first killing off the cells of the immune system
that are actually best equipped to neutralize the virus.
Confronted with a harmful virus, the immune system works to generate
cells capable of producing antibodies perfectly suited to bind and
disarm the hostile invader. These virus-specific B cells proliferate,
secreting the antibodies that slow and eventually eradicate the virus. A
population of these cells retains the information needed to neutralize
the virus and takes up residence in the lung to ward off secondary
infection from re-exposure to the virus via inhalation.
On the surface of these so-called memory B cells are high-affinity
virus-specific receptors that bind virus particles to reduce viral
spread. While such cells should serve at the body’s first line of
defense, it turns out that flu virus exploits the specificity of the
cells’ receptors, using them to gain entry, disrupt antibody production,
and ultimately kill the cells. By dispatching its enemies in this
fashion, the virus is able to replicate efficiently before the immune
system can mount a second wave of defense. This seemingly
counter-intuitive pathway to infection is described this week in the
journal Nature.
“We can now add this to the growing list of ways that the flu virus
has to establish infection,” says Joseph Ashour, a co-author of the Nature paper and a postdoctoral researcher in the lab of Whitehead Member Hidde Ploegh.
“This is how the virus gains a foothold,” adds Ploegh lab postdoc
Stephanie Dougan, also a co-author of the study. “The virus targets
memory cells in the lung, which allows infection to be established—even
if the immune system has seen this flu before.”
Continued: http://wi.mit.edu/news/archive/2013/flu-virus-wipes-out-immune-system-s-first-responders-establish-infection
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