"The B cells have been waiting for at least 60 years if not 90 years for that flu to come around again," Crowe said. "That's amazingbecause it's the longest memory anyone's ever demonstrated."
Crowe's team then fused cells showing the highest levels of activity against the virus with "immortal" cells to create a cell line that secretes monoclonal (or identical) antibodies to the 1918 flu. The antibodies reacted strongly to the 1918 virus and cross-reacted with proteins from the related 1930 swine flu but not to more modern flu strains.
To test if these antibodies still work against 1918 flu in a living animal, Crowe's collaborators at the Centers for Disease Control and Prevention infected mice with the 1918 flu and then administered the antibodies at varying doses. Mice receiving the lowest dose of 1918 antibody and those receiving a non-reactive "control" antibody died. All mice given the highest doses of 1918 antibodies survived.
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."
The findings suggest that B cells responding to a viral infection and the antibody-based immunity that results may last a lifetime, even nine or more decades after exposure.
These antibodies could be used as potential treatments for future outbreaks of flu strains similar to the 1918 virus. And the technology could be used to develop antibodies against other viruses, like HIV.
Most importantly, said Crowe, "the lessons we are learning about the 1918 flu tell us a lot about what may happen during a future pandemic."
|Contact: Craig Boerner|
Vanderbilt University Medical Center