Cocktail of antibodies may block coronavirus infection: Study

Cocktail of antibodies may block coronavirus infection: Study

Washington: A combination of antibodies, including those from a patient who had recovered from the 2002-03 SARS pandemic virus infection, can effectively block the novel coronavirus, according to a study which may lead to new therapeutics against COVID-19.

The study, published in the journal Nature, noted that antibodies, produced by the immune system of recovered people, can neutralise the virus, and help in the development of antiviral treatments or vaccines.

A particular kind of antibodies can target one specific protein on a pathogen, the researchers, including those from the University of Washington in the US, said.

They added that identifying these monoclonal antibodies that can bind to the spike protein found on the novel coronavirus, SARS-CoV-2, and other similar viruses, may aid efforts to treat or prevent COVID-19.

In the research, Davide Corti and his colleagues identified monoclonal antibodies from a patient who recovered from the 2002-03 SARS pandemic disease.

They said these could inhibit SARS-related coronaviruses from both humans and animals.

When the scientists investigated the potential for 25 of these antibodies to inhibit SARS-CoV-2, they found that eight of them could bind to both the free virus, and infected cells.

One candidate, named S309, showed particularly strong neutralising activity against SARS-CoV-2, they said.

By understanding the crystal structure of S309, the scientists demonstrated how the antibody binds to the viral spike protein, which aids in the entry of the pathogen into host cells. They revealed that S309 can act in combination with another, less potent, antibody that targets a different site on the spike protein of the virus. This tandem activity could enhance neutralisation while reducing the chance of resistant mutations emerging, the scientists noted in the study.

Based on the findings, they suggested that cocktails of monoclonal antibodies may be worth exploring to control SARS-CoV-2.

However, the study noted that the results are yet to be validated in humans clinical trials.

Twin antibodies that may help fight COVID-19 identified

Twin antibodies that may help fight COVID-19 identified

Beijing: Scientists have identified a pair of neutralizing antibodies isolated from a patient who recovered from COVID-19 — that may offer therapeutic benefits, and help design molecule antivirals and vaccine candidates to fight the SARS-CoV-2 virus.

The antibodies identified by the researchers, including those from the Chinese Academy of Sciences, bind to the glycoprotein spike of the SARS-CoV-2 virus, blocking the spike’s ability to bind to the human ACE2 receptor and mediate viral entry into host cells.

Preliminary tests of the two antibodies, named B38 and H4, in a mouse model, resulted in a reduction of virus titers, the researchers said.

The finding, published in the journal Science, suggests that the antibodies may offer therapeutic benefits — in addition to informing the design of small molecule therapeutics and vaccine candidates to fight COVID-19, they said.

Researcher Yan Wu from Capital Medical University, China, and colleagues found that the antibodies can each bind simultaneously to different epitopes on the spike’s receptor-binding domain (RBD).

“Due to this binding, both antibodies together may confer a stronger neutralizing effect than either antibody on its own a prediction supported by in vitro experiments,” they said.

This feature also means that should one of the viral epitopes mutate in a way that prevents the binding of one of the two antibodies, the other may still retain its neutralizing activity, according to the researchers.

“By imaging, the structure of the viral spike’s RBD bound to B38, the team confirmed that the antibody binds to a subset of the amino acids bound by ACE2,” they said.

This, the researchers explained, provides an explanation for why the B38 antibody confers such strong neutralizing effects.

They suggest that a “cocktail” containing both antibodies could provide direct therapeutic benefits for COVID-19 patients.

“The finding regarding the viral spike epitopes could also aid the development of small molecule antivirals and vaccine candidates to fight the SARS-CoV-2 virus,” the researchers added.