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Boston Children’s Hospital researchers find antibody that neutralizes all major COVID variants in tests on mice

Charles Krupa/Associated Press

An antibody developed by Boston Children’s Hospital researchers has been shown to neutralize all major variants of SARS-CoV-2, the virus that causes COVID-19, including all Omicron strains, which could lead to a new treatment, the hospital said.

“We hope this antibody will prove to be as effective in patients as it has been in pre-clinical evaluations thus far,” Dr. Frederick Alt of the Program in Cellular and Molecular Medicine at Boston Children’s, a senior investigator on the study, said in a statement. “If it does, it might provide a new therapeutic.”

He said the antibody could “also contribute to new vaccine strategies.”


Using genetically modified mice, hospital researchers, collaborating with colleagues from Duke University, found the antibody SP1-77, which neutralizes the original SARS-CoV-2 strain and its variants including Alpha, Beta, Gamma, Delta, and Omicron, the hospital said.

SP1-77 “potently neutralized all major SARS-CoV-2 variants through the recently emergent BA.5 variant,” researchers said in the study, which was published in August in the journal Science Immunology.

If further research pans out, SP1-77 “would have potential to be a therapeutic against current and newly-arising” variants of concern, said the study, whose first author was Boston Children’s researcher Sai Luo.

The study also suggested that SP1-77 might be “useful in a cocktail” with other currently authorized antibody treatments such as bebtelovimab.

“SP1-77 ... neutralizes these variants by a novel mechanism,” co-author Dr. Tomas Kirchhausen of Boston Children’s said in the statement. “These properties may contribute to its broad and potent activity.”

The researchers are seeking patents for the antibody and the genetically altered mice used to produce it.

“It was a pleasure to work with this dedicated collaborative team whose diverse expertise allowed SP1-77 to be brought to light,” said Alt. He said he looked forward to using the same methods to discover “antibodies with therapeutic potential against other newly emerging pathogens.”


“This is very early-stage proof-of-concept work to illustrate that broadly neutralizing antibodies can be generated using a mouse model,” Dr. Amesh A. Adalja, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security, told Prevention.com. “Such work, if replicated and expanded, could form the basis of new monoclonal antibody products as well as a vaccine.”

Larissa Thackrayan associate professor of infectious diseases at the Washington University School of Medicine who has worked on treatments and vaccines for COVID-19, said what the Boston Children’s researchers had found about the way the antibody worked was intriguing. She said other antibodies have been found to block SARS-CoV-2 by preventing it from binding to cells’ ACE2 receptors.

SP1-77 “works to basically prevent a later step,” she said, blocking the virus from “fusing into the cell and entering into the cell.”

“You may be blocking a more essential process to the virus” she said. The hope would be that, because of that, the virus would have a harder time mutating to get around the antibody, she said.

Thackray noted that researchers have a ways to go before development of a vaccine that gets people to make SP1-77 antibodies.

“They may have a great monoclonal antibody that should be potentially investigated as a therapeutic for use after infection or before infection, but then this idea of a vaccine - that’s a whole other step,” she said. “They would have to see if they can generate a vaccine that would actually provoke that particular antibody response.”


Efforts are underway around the world to develop vaccines that will fend off all variants and intranasal vaccines that will provide increased protection. But Thackray said she would like to see more done. “I strongly feel we actually need more money, more effort,” she said.

While some argue that vaccines already do a good job of preventing severe outcomes, “It would be nice if we could shut down this thing,” she said.

Martin Finucane can be reached at martin.finucane@globe.com.