Written By: Longjam Dineshwori | Updated : December 25, 2021 2:35 PM IST
Annual Flu Shot
Influenza, commonly called the flu, is a contagious viral infection that attacks your respiratory system your nose, throat and lungs. In most cases, the flu resolves on its own, but sometimes, it can lead to deadly complications. According to the World Health Organization (WHO) estimates, the flu kills 290,000 to 650,000 people per year. Young children under age 5, adults older than age 65, pregnant women and people with weakened immune systems are at higher risk of developing flu complications. Therefore, US CDC recommends annual flu vaccination for everyone age 6 months or older to reduce the risk of contracting flu and having serious illness from it. But we may not have to take the annual flu shot in the near future.
Scientists have identified a new Achilles' heel of influenza virus, making progress in the quest for a universal flu vaccine that would be effective against any strain of the virus that can infect humans. The scientist team from Scripps Research, University of Chicago and Icahn School of Medicine at Mount Sinai reported their new discovery in the journal Nature.
The scientists have discovered new antibodies that have the potential to recognize a broad variety of flu strains, even as the virus mutates from year to year. The team said these antibodies bind to a long-ignored section of the virus, which they dubbed the anchor.
"It's always very exciting to discover a new site of vulnerability on a virus because it paves the way for rational vaccine design," said co-senior author Andrew Ward, professor of Integrative Structural and Computational Biology at Scripps Research, as quoted by Science Daily.
Study co-senior author Patrick Wilson elaborated that knowing the sites of vulnerability to antibodies that are shared by large numbers of variant influenza strains can help design vaccines that are less affected by viral mutations.
He said, "The anchor antibodies we describe bind to such a site. The antibodies themselves can also be developed as drugs with broad therapeutic applications."
The discovery also demonstrated there are still new things to discover about the influenza virus, Ward added.
Typically, flu vaccines coax the immune system to generate antibodies that recognize the head of hemagglutinin (HA), a protein found on the surface of the influenza viruses. While the head is the most accessible regions of HA, it also often mutates, necessitating new vaccines.
Researchers have been working on experimental influenza vaccines that stimulate the body to create antibodies against the less-variable stalk region of HA. Some of these vaccines are currently in early clinical trials.
In the new study, the scientists examined the different antibodies present in the blood of people who had either received a seasonal flu vaccine or universal flu vaccine or had been naturally infected with influenza. While many of these antibodies were those already known to recognize either the HA head or stalk, a collection of new antibodies stood out. These were the antibodies bound to the very bottom of the stalk, near where each HA molecule is attached to the membrane of the flu virion. They named this section of HA the anchor.
In total, the scientists identified 50 different anchor antibodies, which could recognize a variety of H1 influenza viruses. In lab tests, some of these antibodies could also recognize pandemic H2 and H5 strains of influenza. When tested in mice, the anchor antibodies showed strong protection against infection by three different H1 influenza viruses.
In future studies, the researchers aim to focus on how to design a vaccine that can induce these anchor antibodies in sufficient numbers.
