People who lived through the 1918 flu pandemic still have antibodies in their immune systems that can recognize and fight that flu virus, although the haven’t been exposed to it for 90 years. Such long-lived immunity was thought to be impossible without periodic exposure to the microbe that stimulated the immune system in the first place [Science News]. Researchers say these antibodies could be helpful in developing treatments for viruses similar to the deadly one that swept around the world in 1918, killing an estimated 50 million people.
For the study, which will be published in this week’s issue of Nature [subscription required], lead researcher James Crowe’s team studied antibodies in the blood of 32 people in their 90s and 100s, born during or before 1915. They found that all 32 people had antibodies to the 1918 strain of flu virus [HealthDay News]. In lab tests, the antibodies mounted a powerfully effective attack against a modern version of the virus. “This is entirely counter to everyone’s intuition — that elderly people would have such potent antibodies,” Crowe says. Aging typically reduces a person’s ability to build antibodies and develop immunity to diseases [Science News].
The 1918 flu was an H1N1 strain that apparently came straight from birds [Reuters]. Researchers are particularly interested in studying it because a newer strain of bird flu, H5N1, is currently circulating among bird populations in Asia, Africa, and Europe, and has crossed over to infect 385 people since 2003, killing 243. Experts fear that, like the H1N1 virus did in 1918, H5N1 will mutate into a form that passes easily among people and spark another pandemic [Reuters].
Researchers say the antibodies harvested from the centenarians’ immune systems are still potent and useful. “If you take the cells that make these antibodies and you can treat them in a way to allow them to grow in culture dishes for a long period of time, you can then isolate those antibodies and use those antibodies to treat somebody with a severe infection,” said Jeffrey Taubenberger, a 1918 flu virus expert [NPR]. Sure enough, when researchers treated lab mice with the antibodies and then infected them with a modern version of the 1918 flu virus, the mice didn’t get sick.
Image: National Musuem of Health and Medicine