This article is more than 5 years old. Information may no longer be current.
Developed flu antibodies may be stronger with first-time exposure
Influenza A(H5N1) antibodies created by the body when encountering the virus for the first time could be more useful in developing a vaccine than those from repeat exposure, according to findings published in Proceedings of the National Academy of Sciences.
Ali Ellebedy, PhD, director of the Emory Vaccine Center, and colleagues analyzed levels of antibodies directed against different parts of the hemagglutinin protein in 17 volunteers, before and after vaccination. More antibodies were created before vaccination that targeted the protein’s stem, whereas those produced after vaccination targeted the protein’s head.
“Our findings delineate a potential vaccination strategy where H5N1 or H7N9 immunization could be used not only for immunologically priming the population to quickly respond to serious pandemic influenza threats, but also for generating broadly neutralizing antibodies against influenza in humans,” the researchers wrote.
In recent years, researchers have found the stem of the hemagglutinin protein mutates less than other regions, and it could be the basis for a vaccine that is protective against a variety of influenza strains.
In 2008 and 2009, Emory Vaccine Center researchers had found participants infected with the 2009 H1N1 pandemic influenza strain developed broadly cross-reactive antibodies. When the H1N1 strain began to circulate and was added to the standard seasonal trivalent vaccine, participants generated antibodies that primarily reacted to the head region of hemagglutinin.
“Our previous research led us to hypothesize that immune responses to the stem region are likely to be stronger after exposure to hemagglutinin molecules derived from flu viruses which the human population has been minimally exposed to,” Ellebedy said in a press release. “We had already performed a big H5N1 study back in 2008, so we went back and tested our hypothesis with some novel reagents that allowed us to dissect responses that are directed to the head vs. the stem regions.” — Dave Muoio
Disclosure: The researchers report no relevant financial disclosures.