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A new epitope for universal influenza vaccines has been discovered in a study.

A of scientists has discovered an point of vulnerability in the influenza virus’s genetic makeup. The findings of the study were published in the ‘Nature Journal’.

According to the findings, a small subset of antibodies elicited by experimental and existing influenza specifically targeted a site at the base, or anchor, of the influenza hemagglutinin (HA) protein—an “epitope” whose significance had previously gone unnoticed in previous influenza antibody research.

Experimental in cultures and mice suggests that antibodies against this “anchor epitope” can neutralize a wide range of influenza strains, including those with pandemic potential, according to the .

Weill Cornell Medicine’s Gale and Ira Drukier Institute for Children’s Health recruited Dr Patrick Wilson as a professor of pediatrics and a scientist to work on the study’s co- author Dr Patrick Wilson. “This will now be one of the key influenza epitopes that we as we develop candidate universal influenza and antibody therapies,” Wilson said.

The majority of the research was carried out while Dr Wilson was a student at the University of Chicago. Dr. Jenna Guthmiller, a co-first author, worked as a postdoctoral researcher in his laboratory at the time and is still employed by that institution. Professor Andrew Ward of the Department of Integrative Structural and Computational Biology at Scripps Research collaborated on the study with Drs. Wilson and Guthmiller, who served as co-senior author along with Dr. Ward. Dr Julianna Han, a co-first author on the paper, works as a staff scientist in the Ward laboratory.

According to Dr. Ward, discovering a new site of vulnerability on a is “always very exciting” because it “paves the way for rational vaccine design.”

As he continued, “It also shows that despite all of the years and effort put forth in influenza vaccine research, there are still new things to discover.”

Influenza particles are densely packed with copies of the HA protein, which is the primary viral protein that antibodies can recognize. Over time, this protein underwent mutations that caused it to differ from one influenza strain to the next. As a result, neutralizing antibodies that target the HA of one strain are often ineffective against other strains. The current “seasonal” influenza are considered to be of limited efficacy because they are designed to protect against only two or three prevalent strains, which is considered to be a significant limitation.

Despite the high variability of influenza viruses, scientists have discovered relatively constant sites on the HA protein, to which antibodies can bind and neutralize the of a wide range of strains over the past two decades. These sites have been identified on the HA protein by scientists over the past two decades. These “broadly neutralizing” “epitopes” are being studied as potential targets for “universal” influenza and antibody-based therapies, or at the very least for vaccines that are “broadly protective.”

As part of their research, the team looked at antibodies induced by an experimental universal influenza vaccine that was being developed at the time, as well as antibodies induced by seasonal influenza vaccines and natural influenza infections. The researchers discovered that a significant proportion of the elicited antibodies bound to the lower, stalk portion of HA, which is generally less variable in influenza viruses than the upper, head portion.

The use of electron microscopy revealed that some of the stalk-targeting antibodies—including a surprisingly high proportion of antibodies from the experimental vaccine recipients—bound to an epitope at the very bottom of the HA stalk, where the stalk is anchored to the viral membrane, which had previously gone unnoticed.

These anchor epitope antibodies have been shown to neutralize a wide range of influenza strains that contain the H1 subtype of the HA protein, as well as cross-react with H2 and H5 strains in animal and cell culture experiments, according to the researchers. The influenza subtypes H1, H2, and H5 together account for a significant proportion of seasonal and pandemic-threat influenza viruses in humans.

The researchers also discovered that the majority of human antibody-producing cells are capable of producing antibodies against anchor epitopes, which further supports the idea that the anchor epitope could be used as a vaccine target.

“In order to increase our protection against these rapidly mutating viruses, we need to have as many tools as possible,” Dr Han continued, ,

“With this discovery, we have added another highly effective target to our arsenal,” she continued.

Antibodies against the anchor epitope were only weakly induced by conventional seasonal influenza vaccines. The challenge, according to the scientists, will be to develop a vaccine that accurately mimics the anchor epitope of HA while also being able to induce these antibodies in large numbers.

Using modern protein engineering methods to create a vaccine that can induce sufficient numbers of antibodies against this epitope, Dr Guthmiller explained that the human immune system already has the capability of producing antibodies against this epitope.

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