Researchers identify new antibodies that could improve flu vaccines

ISLAMABAD, DEC 22 (ONLINE): For most people, coming down with influenza — more commonly known as the flu — is not a major health issue. They will feel sick for four to seven days, then symptoms will subside.
However, there are populations where the flu can cause more serious health concernsTrusted Source, including older adults over the age of 65, pregnant people, children under the age of 5, and people with certain medical conditions such as heart disease, diabetes, and asthma.”

This is why groups like the Centers for Disease Control and Prevention (CDC)Trusted Source in the United States and the European Centre for Disease Prevention and Control recommend people get an annual influenza vaccine, especially those in high risk groups. A recent CDC health advisory warned that current vaccination rates against respiratory viruses are low in the U.S.
Because influenza viruses are always changing, influenza vaccines are changed yearly to protect against the strains predicted to be the most prevalent during flu season.

Additionally, influenza viruses are very diverse. For example, influenza A virusesTrusted Source, which contribute to seasonal epidemics each year along with influenza B, can be further divided into various subtypes before eventually being classified as individual strains. The flu vaccine works betterTrusted Source for certain strains and is less effective against others.

Now, researchers from the University of Pittsburgh have identified a new class of antibodies capable of combating multiple flu virus subtypes.

Scientists believe this new research — published December 21 in the journal PLOS Biology — could help develop a flu vaccine with broader protection across different strains.

How do flu antibodies work?
According to Dr. Kevin McCarthy, assistant professor of microbiology and molecular genetics at the Center for Vaccine Research at the University of Pittsburgh and senior author of this study, although antibodies provide the strongest protection against flu virus infection, the virus continually evolves to escape them.

“Multiple co-circulating flu subtypes make it difficult to get a match between circulating viruses and components in vaccines,” Dr. McCarthy told Medical News Today.

“The antibodies in our study are capable of blocking multiple flu virus subtypes at once.”

Although all approved influenza vaccines train the immune system to make antibodies against the flu virus for future encounters, he explained that the influenza virus evolves to evade these antibodies, which is why updated vaccines are needed.

“The antibodies we identified demonstrate that the hurdles to making improved vaccines that resist year-to-year changes may be lower than previously believed. We also highlight that specific vaccine manufacturing processes may introduce errors that may ‘distract’ the immune system from achieving an optimal response.”

— Dr. Kevin McCarthy, senior study author
Alternatives to egg-based flu vaccines
For this study, Dr. McCarthy and his team focused on finding a new to neutralize a small change found in some H1 fluTrusted Source subtypes that affect the sequence of building blocks that make up hemagglutininTrusted Source — a type of protein that binds receptors on red blood cells to initiate the early stage of a viral infection.

According to scientists, while certain antibodies can stop H1 and H3 fluTrusted Source subtypes, they are no longer able to when the hemagglutinin is modified.
Using blood samples, researchers uncovered a new class of antibodies capable of destroying certain H3 flu strains and certain H1 flu strains with or without the hemagglutinin modification.
“We have two major findings,” Dr. McCarthy reported.

“First, it appears that some humans can produce strong antibody responses that block infection by multiple influenza subtypes. A proper series of exposures is likely required but the barriers to achieving these responses are lower than we anticipated. With this information, improved vaccines can be designed and tested in the laboratory.”.

“Second, some types of vaccine production like growing vaccines in eggsTrusted Source can introduce changes that misdirect antibodies from their intended targets, the viruses transmitting between people,” he added.

“Transitioning away from egg-grown vaccines, for which there are already alternatives, would minimize this issue.”

New flu antibodies could offer greater protection
MNT also spoke about this study with Dr. David Cutler, a board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA.

Dr. Cutler said the discovery of a new type of antibody to protect against influenza offers promise to reduce the disease and death caused by various flu viruses.

“Whereas some viral diseases, like smallpox, polio, and measles, have either been eradicated or markedly reduced in their impact by vaccines, influenza continues to kill thousandsTrusted Source in this country every year,” he explained.

“What has made influenza more difficult to prevent is the rapid mutation of the virus, especially at certain sites, designated hemagglutinin and neuraminidaseTrusted Source. These sites give the flu virus its classic designation, such as H1N1, or H3N2. Presumably, antibodies (that) latch onto more sites (that) have less variation could be more widely effective in protecting against the flu. This is the promise offered by this new class of antibodies.”

— Dr. David Cutler, family medicine physician