CORRECTED – Swine flu survivors developed super flu antibodies

(Corrects number of flu deaths and makes clear antibody being
tested from NIH and not Crucell)

* Antibody study points way to “universal” flu vaccine

* Suggests teams are on the right track

By Julie Steenhuysen

CHICAGO, Jan 10 (BestGrowthStock) – A study of antibodies from
people infected with H1N1 swine flu adds proof that scientists
are closing in on a “universal” flu shot that could neutralize
many types of flu strains, including H1N1 swine flu and H5N1
bird flu, U.S. researchers said on Monday.

They said people who were infected in the H1N1 pandemic
developed an unusual immune response, making antibodies that
could protect them from all the seasonal H1N1 flu strains from
the last decade, the deadly “Spanish flu” strain from 1918 and
even a strain of the H5N1 avian flu.

“It says that a universal influenza vaccine is really
possible,” said Patrick Wilson of the University of Chicago,
who worked on the paper published in the Journal of
Experimental Medicine.

Many teams are working on a “universal” flu shot that could
protect people from all flu strains for decades or even life.

U.S. officials say an effective universal flu vaccine would
have enormous ramifications for the control of influenza, which
kills anywhere from 3,300 to 49,000 people in the United States
each year.

Wilson’s team started making the antibodies in 2009 from
nine people who had been infected in the first wave of the H1N1
swine flu pandemic before an H1N1 vaccine had been produced.
The hope was to develop a way to protect healthcare personnel.

Working with researchers from Emory University School of
Medicine, the team produced 86 antibodies that reacted with the
H1N1 virus, and tested them on different flu strains.

Of these, five were cross-protective, meaning they could
interfere with many strains of flu including the 1918 “Spanish
flu” and a strain of H5N1 or avian flu.

Tests of these antibodies in mice showed they were fully
protected from an otherwise lethal dose of flu.

And some of these cross-protective antibodies were similar
in structure to those discovered by other teams as having
potential for a universal flu vaccine.

“It demonstrates how to make a single vaccine that could
potentially provide permanent immunity to all influenza,”
Wilson said in a telephone interview.

“LOLLIPOP STICK”

Flu vaccines and drugs focus on proteins found on the
surface of the flu virus called hemagglutinin and
neuraminidase, which give influenza A viruses their names, as
in H5N1 or H1N1.

Hemagglutinin is a lollipop-shaped structure with a big,
round head. This head is so large it attracts most of the
immune system antibodies, but it mutates readily.

Two years ago, researchers working for Crucell NV (CRCL.AS: )
and a separate team found that antibodies that attach to the
“stick” or stalk part of the hemagglutinin lollipop mutate much
less — providing a perfect target for a vaccine that could
neutralize a range of different flu viruses.

“Previously, this type of broadly protective,
stalk-reactive antibody was thought to be very rare,” Jens
Wrammert of Emory said in a statement. But in the H1N1
patients, he said, they were “surprisingly abundant.”

That may be because the H1N1 virus was so different from
other flu strains that the immune system made antibodies for
the only parts of the virus it recognized — this “stick” or
stalk region that is common to many flu strains.

Wilson said the study proves it is possible to get the
immune system to make these antibodies if it has the right
stimulation. The team is working with an unnamed biotechnology
company to develop a vaccine or drugs based on this notion.

And a team at the National Institutes of Health is testing
a two-step vaccine that uses DNA from stalk-reactive antibodies
to “prime” the immune system, followed by a regular flu shot.

A study in July showed this two-step approach protected
mice and ferrets against flu strains from 1934 through 2007.
This vaccine is now being tested in people.
(Editing by Cynthia Osterman)