BY KORIN MILLER PUBLISHED: SEP 6, 2022
COVID-19 vaccines have been effective at keeping people from getting severely ill and dying from the virus, but they’ve required different boosters to try to keep on top of all of the coronavirus variants that have popped up. Now, researchers have discovered an antibody that neutralizes all known COVID-19 variants.
The antibody, called SP1-77, is the result of a collaborative effort from researchers at Boston Children’s Hospital and Duke University. Results from mouse studies they’ve conducted were recently published in the journal Science Immunology, and they look promising.
But what does it mean, exactly, to have an antibody that can neutralize all variants of COVID-19, and what kind of impact will this have on vaccines in the future? Here’s what you need to know.
What is SP1-77?
SP1-77 is an antibody developed by researchers that so far can neutralize all forms of SARS-CoV-2, the virus that causes COVID-19. It was created after researchers modified a mouse model that was originally made to search for broadly neutralizing antibodies to HIV, which also mutates.
The mice used in the study have built-in human immune systems that mimic the way our immune systems develop better antibodies when we’re exposed to a pathogen. The researchers inserted two human gene segments into the mice, which then created a range of antibodies that humans might make. The mice were then exposed to SARS-CoV-2’s spike protein (which is what the virus uses to latch onto your cells) and produced nine different families of antibodies that bound to the spike protein to try to neutralize it.
Those antibodies were then tested and one—SP1-77—was able to neutralize Alpha, Beta, Gamma, Delta, and all Omicron strains (including the current circulating ones) of COVID-19.
The antibody works in a slightly different way than many of the antibodies people make to vaccines. To infect you, SARS-CoV-2 has to first attach to ACE2 receptors in your cells. The current COVID-19 vaccines block this binding from happening by attaching to the spike protein’s receptor-binding domain (RBD) at certain spots, a press release from Boston Children’s Hospital explains.
The SP1-77 antibody also binds to the RBD, but doesn’t prevent the virus from binding to ACE2 receptors. What it does do is block the virus from fusing its outer membrane with the membrane of your cells, which is what needs to happen to make you sick.
“SP1-77 binds the spike protein at a site that so far has not been mutated in any variant, and it neutralizes these variants by a novel mechanism,” study co-author Tomas Kirchhausen, Ph.D., said in a statement. “These properties may contribute to its broad and potent activity.”
What does this mean for the future of COVID-19 vaccines and treatments?
It’s not clear right now. It’s important to note that this research was done in mice—not humans—although studies on the antibody are ongoing.
“This is very early-stage proof-of-concept work to illustrate that broadly neutralizing antibodies can be generated using a mouse model,” says Amesh A. Adalja, M.D., infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security. “Such work, if replicated and expanded, could form the basis of new monoclonal antibody products as well as a vaccine.”
Experts say that a vaccine that could take out all variants of COVID-19 would definitely be welcome. “We’d love to have a vaccine that is active against all circulating variants, including those yet to come,” says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. “It’s the holy grail of vaccines.”
That could potentially mean that you would only need to get a COVID-19 shot or booster once a year or even less frequently, depending on how long protection from the vaccine lasted, Dr. Russo says.
The researchers have applied for a patent for the SP1-77 antibody and mouse model used to create it, and plan to create something that can be used by the general public if all goes well.
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