• Posted December 29, 2023

Could Antibody Discovery Lead to Better Flu Vaccines?

Researchers appear to have discovered a new weapon in the war on a particularly difficult foe.

They have identified a previously unrecognized class of antibodies that seem to be capable of neutralizing multiple strains of the flu virus.

Their findings, recently reported in the journal PLOS Biology, could lead to development of a vaccine that protects more broadly against influenza.

Each year, new vaccines are offered based on experts' best guesses about which strains will dominate. Sometimes they guess right, other times, not so much.

"We need annual influenza virus vaccines to keep pace with continuing viral evolution," the authors said in a journal news release. "Our work suggests that the barriers to eliciting more broadly protective immunity may be surprisingly low."

An array of studies are paving the way for vaccines that protect against multiple strains.

Many are focused on antibodies that can protect against flu subtypes known as H1 and H3 at the same time. These come in multiple strains and cause widespread infection.

Led by Holly Simmons of the University of Pittsburgh's School of Medicine, researchers in this study zeroed in on one target.

They focused on a small change found in some H1 strains in the sequence of building blocks that makes up hemagglutinin, a protein that plays a key role in the early stage of infection.

Some antibodies that neutralize H3 can also neutralize H1, but not if its hemagglutinin has this change, dubbed the 133a insertion, researchers explained.

Using blood samples from patients, they identified a class of antibodies that can neutralize some H3 strains as well as some H1 strains with or without the 133a insertion.

A vaccine coaxes the immune system to make antibodies that can bind to hemagglutinin and stop it from invading a person's cells. Different antibodies bind to parts of hemagglutinin differently, and the virus also changes over time, resulting in new strains that can evade the old antibodies.

Researchers said this work expands the list of antibodies that could possibly contribute to development of a vaccine with broader protection. It also adds to growing evidence supporting changes in how flu vaccines are manufactured, they added.

More information

Learn more about vaccines at the U.S. Centers for Disease Control and Prevention.

SOURCE: PLOS Biology, news release, Dec. 21, 2023