The authors of the discovery are scientists from the Scripps Research Institute, the University of Chicago, and the Icahn School of Medicine in Mount Sinai (all in the US). They described a class of antibodies targeting a part of the virus that had been initially omitted in the study and initially called the “anchor”. These antibodies have the potential to recognize a wide variety of influenza strains – even as the virus mutates from year to year.
“It’s always very exciting to discover a new vulnerability site for a virus, as it paves the way for more effective vaccine design,” says co-author Prof Andrew Ward of Scripps Research. flu, you can still discover new things. “
“By identifying antibody susceptibility sites that are common to a large number of influenza variants, we can design vaccines that are less dependent on viral mutations – adds Dr. Patrick Wilson, another co-author of the study. “The anchor antibodies we describe in our work bind to this very site.”
On average, flu affects more than 20 million people in the United States each year and leads to over 20,000 people. deaths. In Poland, 3-5 million people suffer from influenza every year in the last decade.
Vaccines against this disease usually cause the immune system to produce antibodies that recognize haemagglutinin (HA), a protein that protrudes from the surface of the virus. The peak region of this protein (the head portion) is the most accessible region, making it a good target for the immune system; unfortunately it is also one of the most variable (mutating) parts of the virus. That is why vaccines have to be modified from year to year in order to “keep up” with mutations.
For several years, scientists from around the world have been trying to develop vaccines that would be more universal, because they would stimulate the body to create antibodies against the less variable region of HA (the stem part). Several such universal formulations are currently in the early stages of clinical trials.
In their latest experiment, an intercollegiate research team characterized 358 different antibodies in the blood of people who were either given the seasonal flu vaccine, the experimental vaccine in Phase I clinical trials, or were naturally infected with the flu virus.
Many of the antibodies detected were known to scientists: they recognized either the head portion or the stem portion of HA. However, a completely new class of antibodies has also been noticed – bind to haemagglutinin at the very bottom of the stem, near the region where each HA molecule is attached to the membrane of the influenza virion.
Scientists named this part anchorand then began further testing. As a result, they identified 50 different antibodies against the HA anchor in 21 different people. These antibodies were found to recognize different variants of the H1 influenza virus, corresponding to several seasonal strains. Some antibodies in laboratory tests were also able to recognize pandemic strains of H2 and H5 influenza.
“To strengthen our protection against highly mutant viruses, we need to have as many tools as possible,” the authors say. This discovery adds a new, very powerful tool to our pool “.
It is extremely important that the antibodies detected appear to be fairly common in the human population and belong to a class that can be produced by all of us. This is a very important part of the vaccine design process.
“The human immune system already has the ability to produce antibodies against this region of the HA protein, so it is enough to use modern protein engineering methods to create a vaccine that will induce their production at a sufficient level” – explained the researchers in the publication.
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