Antibody targeting variety of flu viruses may be key to 'a truly universal vaccine', says study
The lack of universal flu vaccines was felt during the 2009 swine-flu pandemic, which claimed the lives of half-a-million people worldwide.
Scientists from Washington University have taken their first step towards developing a universal vaccine against several cases of flu. The team has identified a likely vaccine candidate: an antibody that could target a variety of flu viruses.
The study was performed in mice. The authors demonstrate that the antibody was effective against 12 strains of the virus: it saved the lives of all the mice, in spite of them having lethal levels of the flu virus.
Developing a universal flu vaccine has been a distant dream and scientists are trying to address this. Though we have flu vaccines, they are effective against a few selective varieties. The lack of universal flu vaccines was felt during the 2009 swine-flu pandemic, which claimed the lives of half-a-million people worldwide.
"There are many strains of influenza virus that circulate, so every year we have to design and produce a new vaccine to match the most common strains of that year," said co-senior author Ali Ellebedy, an assistant professor of pathology and immunology at Washington University. "Now imagine if we could have one vaccine that protected against all influenza strains, including human, swine and highly lethal avian influenza viruses. This antibody could be the key to the design of a truly universal vaccine."
The source of the antibody can be traced back to a patient suffering from the flu. In her blood, the team found antibodies that were acting differently: it was found targeting something else, instead of the known major protein found on the surface of the virus. In order to identify the targets of the three antibodies, the scientists began to dig deeper. In their investigation they found at least one of the three antibodies acted against a protein found on the surface of influenza: neuraminidase. The antibody was effective against viral strains that affected humans and non-humans.
Flu viruses depend on this protein to increase their numbers. It helps the newly formed viruses move to new cells and infect them. After identifying the antibody and the target viral protein, the research team wanted to check whether the antibody was preventing the virus from spreading. For that, they infected mice with a lethal dose of the flu virus and checked for their mice.
All the mice, given one particular antibody, survived. It protected them against 12 strains of the virus. The antibody — called 1G01 — was clearly the winner.
The team will now look at developing new and improved treatments and vaccines for influenza based on antibody 1G01.
Talking about the significance of the study, Ellebedy said, "Neuraminidase has been ignored as a vaccine candidate for a long time. These antibodies tell us that it should not have been overlooked. Now that we know what a broadly protective antibody to neuraminidase looks like, we now have an alternative approach to start designing novel vaccines that induce antibodies like this. And that could be really important if we are going to figure out how to design a truly universal vaccine."
The study has been published in Science.