H3N2 virus developed that’s resistant to antibodies

Written by Jann Janzen, CNN

If you want an easy way to see where your needle has been, look at your swabs. (OK, maybe that might not be true.)

Now scientists have engineered a strain of influenza A (H3N2) viruses that are resistant to the so-called antigenic antibody response — which is the very antibodies that help us fight off infection. This particular version of H3N2 is called COVID-19 and was developed by a team led by scientists at Brown University and Southern Illinois University School of Medicine.

The study, published this week in the journal Cell Reports, is the first to offer significant clues as to how evolution may be changing flu viruses.

According to Martin Gerber, a co-author of the study, it’s been some time since an influenza virus introduced a new strain that is resistant to the same or other parts of an organism’s structure.

“In the last 20 years, there’s been no real innovation,” he told CNN. “You go back to the big pandemics, but now there’s only one vaccine for each virus.”

He said an influenza virus can evolve to be more virulent if it is introduced into an environment where it is undefended by antibodies. COVID-19 breaks from the rules set by standard H3N2 viruses.

“The structure of the virus is very similar to that of the more commonly used H3N2 strain,” said Andrew Browdy, a co-author of the study. “But this COVID is able to evade the antigenic antibody response to that type of protein.”

Conversely, the vaccine antibodies that provoke a strong antibody response to one new strain of H3N2 may prove ineffective against this new strain.

‘It’s mind-boggling’

COVID-19 isn’t the first innovation to emerge from the world of flu research. Most of the traits that drive the virus evolution can be traced back to a changing environment, according to Paul Meecham, director of the Vaccine Research Center at the Emory Vaccine Center.

For example, H3N2 viruses are often found in pigs, where they’re more closely associated with hamsters than humans, so there’s been some research about how changes in that environment could result in new strains.

Other emerging patterns have to do with the way viruses in the past were controlled. Once egg-based techniques were replaced by synthetic techniques, researchers discovered that the viral strains that develop best for human containment were those that did not have the same genes that facilitate the digestion of proteins such as hemagglutinin (H3N2’s dominant protein).

Those resistant to the destruction of the H3N2 hemagglutinin do exist, but they’re nearly always in small populations, noted Gerber.

“This is just a new version of a virus that has adapted to the antigenic environment and is able to survive the immune response. They’ve adapted very rapidly,” he said.

And the virus whose patterns include the same protein only makes it more difficult to develop vaccines for it. Researchers at the Emory Vaccine Center recently published a study using computer models to test what they might look like to develop a vaccine to COVID-19.

The advantage that other viruses have in the face of COVID-19, says Gerber, is that “they have a very efficient and consistent transformation of themselves.”

“It’s really an arms race,” he said. “If an experimental model against COVID-19 can’t generate results, then (a vaccine using) COVID-19 can’t generate the results you want.

In fact, scientists are currently attempting to kill COVID-19.

From ‘tabula rasa’ to ‘prototypic genome’

But as recent events around the world have demonstrated, the most insidious aspect of an evolved flu virus is its potential to spread and kill.

Gerber said this particular COVID isn’t the first time he’s seen different kinds of H3N2 mutations.

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