Study finds new target for universal flu vaccine

More progress is being made in the pursuit of developing a universal flu shot.

Scientists at Scripps Research, University of Chicago, and Icahn School of Medicine at Mount Sinai have identified a new vulnerability in the influenza virus. Antibodies against a section of the virus, which the team named “the anchor,” have the potential to recognize a broad variety of flu strains, even as the virus changes from year to year, according to Scripps Research. The study has been published in the journal, Nature.

A collaborative team of scientists characterized 358 different antibodies present in the blood of individuals who had either been given a seasonal influenza vaccine, were in a phase I trial for an experimental, universal influenza vaccine, or had been naturally infected with influenza, according to researchers.

Many of the antibodies present in the blood of participants were antibodies already known to recognize either the HA head or stalk. But a collection of new antibodies stood out; the antibodies at the very bottom of the stalk, near where each HA molecule is attached to the membrane of the flu virion.

This section was dubbed “the anchor” and the study’s co-first authors, Julianna Han, PhD,  scientist in the Ward lab at Scripps Research, and Jenna Guthmiller, PhD, postdoctoral fellow at the University of Chicago, began studying it further. They identified 50 different antibodies to the HA anchor, from a total of 21 individuals.

They discovered the antibodies recognized a variety of H1 influenza viruses, which account for many seasonal flu strains. Some of the antibodies were also able to recognize pandemic H2 and H5 strains of influenza in lab tests, according to Scripps Research. And in mice, the antibodies successfully protected against infection by three different H1 influenza viruses.

In the future, improved iterations of a universal vaccine could more purposefully aim to generate anchor antibodies, according to scientists. Ideally, a universal influenza vaccine will lead to antibodies against multiple sections of the virus—such as both the HA anchor and the stalk—to increase protection to evolving viruses.

“In order to increase our protection to these highly mutating viruses, we need to have as many tools as we can,” said Han. “This discovery adds one more highly potent target to our repertoire.”