Diseases Antibodies in 1918 Flu Survivors Effective 90 Years Later
By Ben Wasserman
Aug 18, 2008 - 8:51:31 AM
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MONDAY AUGUST 18 (foodconsumer.org) -- U.S. researchers
have discovered that infection and natural exposure to the 1918 influenza virus
induced antibodies that made survivors immune to the disease ninety years later.
The researchers produced antibodies with cells isolated
from these survivors and demonstrated the immunity against the highly lethal
1918 flu virus in mice.
The finding suggests that the antibodies can be used as
an effective treatment for another virus similar to the 1918 flu breaks out in
the future.
The 1918 flu pandemic worldwide killed an estimated 50
million people.
Health officials worldwide
worry that a similar flu pandemic may strike some time in the future,
potentially killing millions of people.
The study titled "Neutralizing antibodies derived
from the B cells of 1918 influenza pandemic survivors," was published in
the advanced online edition of the journal Nature.
"Ninety years after survivors encountered the 1918
pandemic influenza virus, we collected antibody-producing B cells from them,
and successfully isolated B cells that produce antibodies that block the viral
infection," said contributing author Dr. Christopher Basler, PhD,
Associate Professor of Microbiology at Mount Sinai School of Medicine.
"The antibodies produced by these cells demonstrated
remarkable power to block 1918 flu virus infection in mice, proving that, even
nine decades after infection with this virus, survivors retain protection from
it."
"The fact that you can isolate these anti-1918
memory B cells so long after infection will hopefully provide the impetus to
further study the mechanisms behind long lived immunity," said Dr. Osvaldo
Martinez, post-doctoral fellow at Mount Sinai School of Medicine.
For this study, Dr. Eric Altschuler at the University of
Medicine and Dentistry of New Jersey recruited 32 individuals age 91-101 years
and lived through the influenza pandemic to donate blood. Dr. Basler's lab
tested the blood and found that antibodies recognize the 1918 virus.
Dr. James Crowe and colleagues at Vanderbilt University
produced antibodies from these individuals' blood cells and Dr. Basler's lab
demonstrated the potent neutralizing activity of the antibodies against 1918
virus.
The virus was resurrected in 2005 by researchers from
Mount Sinai and the Armed Forces Institute of Pathology from the bodies of
people killed in the outbreak and preserved in the permanently frozen soil of
Alaska.
Antibodies were also provided to Dr. Terrence Tumpey at
the Centers for Disease Control and Prevention to test in mice the potency of
the antibodies derived from the 1918 survivors.
Crowe's lab isolated extremely rare B cells from eight
samples to produce antibodies in culture and found seven were able to produce
antibodies to a 1918 virus protein.
Then Crowe's team fused cells with the highest levels of
activity against the virus with immortal cells to create cells that secrete
monoclonal antibodies to the 1918 flu virus.
The antibodies thus made reacted strongly to the 1918
virus and cross-reacted with proteins from the related 1930 swine flu virus,
but not more modern flu strains.
Crowe in collaboration with the CDC tested the immunity
of these antibodies in mice and found those who received the low doses died
while those who received high doses all survived after exposure to the 1918 flu
virus.
Although aging typically causes immunity to weaken,
"these are some of the most potent antibodies ever isolated against a
virus," Crowe said. "They're the best antibodies I've ever
seen."
"Our findings show that survivors of the pandemic
have highly effective, virus neutralizing antibodies to this powerful virus,
and humans can sustain circulating B memory cells to viruses for up to 9
decades after exposure," said Dr. Tshidi Tsibane, post-doctoral fellow at
Mount Sinai School of Medicine. "These findings could serve as potential
therapy for another 1918-like virus."