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Researchers at Washington University have identified
two antibodies that protect animals from disease
caused by alphaviruses. The antibodies worked for
every alphavirus tested, meaning they potentially
could form the basis of treatments or serve as a
template for a universal vaccine. In the U.S., the
alphavirus is an important concern, most about is
chikungunya virus, which can cause debilitating
arthritis, but it’s also seen in the cases of
encephalitis caused by Eastern equine encephalitis
virus. Alphaviruses used to be limited to the
tropics, but in recent years they've been spreading
into new geographic areas. Most are still uncommon,
but together they cause millions of infections and a
considerable burden of disease, and there is no
specific therapies or vaccines for any of them. The
alphavirus group includes more than 30 species,
split into two branches. Viruses such as
chikungunya, Mayaro, O'nyong-nyong and Ross River,
all of which cause fever, rash and arthritis,
historically had been limited to Africa, Asia and
Europe. However, beginning in 2013, chikungunya
worked its way into the Caribbean and parts of North
and South America. The other branch of alphaviruses,
found in the Americas, includes Eastern, Western and
Venezuelan equine encephalitis viruses and causes
brain infections. To find antibodies that would
protect against the whole alphavirus group, a group
of researchers screened a set of antibodies produced
by two people who had been infected with chikungunya
virus. They tested the antibodies against a panel of
alphaviruses representing both branches of the
group. Two antibodies recognized all of the
alphaviruses tested. Further experiments showed that
the antibodies worked by blocking developing virus
particles from exiting one cell en route to
infecting another. The antibodies attach to part of
a viral protein called E1 that is exposed only
during the exiting process. Once the virus has fully
formed and detached from the cell, the E1 protein is
folded into the virus particle and hidden.
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