Researchers at Washington University School of Medicine in St. Louis have identified an antibody that is highly protective at low doses against a wide range of viral variants. Moreover, the antibody attaches to a part of the virus that differs little across the variants, meaning that it is unlikely for resistance to arise at this spot.
Below is a summary of their publication on "Immunity" journal.
"With the emergence of SARS-CoV-2 variants with increased transmissibility and potential resistance, antibodies and vaccines with broadly inhibitory activity are needed. Here wedeveloped a panel of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) that bound the receptor binding domain of the spike protein at distinct epitopes and blocked virusattachment to its host receptor, human angiotensin converting enzyme-2 (hACE2). Although several potently neutralizing mAbs protected K18-hACE2 transgenic mice against infection caused by ancestral SARS-CoV-2 strains, others induced escape variants in vivo or lost neutralizing activity against emerging strains. One mAb, SARS2-38, potently neutralized all SARS-CoV-2 variants of concern tested and protected mice against challenge by multiple SARS39 CoV-2 strains. Structural analysis showed that SARS2-38 engaged a conserved epitope proximal to the receptor binding motif. Thus, treatment with or induction of neutralizing antibodies that bind conserved spike epitopes may limit the loss of potency of therapies or vaccines against emerging SARS-CoV-2 variants."
PS: This team studied the Covid virus on mice and obtained 43 antibodies from them that recognize the RBD (receptor-binding domain). Then they selected nine of the most potent neutralizing antibodies and tested on mice to see whether they could protect animals infected with the original SARS-CoV-2 from disease. Multiple antibodies passed both tests, with varying degrees of potency.
Then they selected the two antibodies that were most effective at protecting mice from disease and tested them against a panel of viral variants. The panel comprised viruses with spike proteins representing all four variants of concern (alpha, beta, gamma and delta), two variants of interest (kappa and iota), and several unnamed variants that are being monitored as potential threats.
One antibody, SARS2-38, easily neutralized all the variants. Moreover, a humanized version of SARS2-38 protected mice against disease with all variants.
To conclude, Prof Michael S Diamond (Professor of Molecular Microbiology and of Pathology & Immunology.) says "This antibody is both highly neutralizing (meaning it works very well at low concentrations) and broadly neutralizing (meaning it works against all variants).
Also, it binds to a unique spot on the spike protein that isn't targeted by other antibodies under development. That's great for combination therapy. We could start thinking about combining this antibody with another one that binds somewhere else to create a combination therapy that would be very difficult for the virus to resist."
Below is a summary of their publication on "Immunity" journal.
"With the emergence of SARS-CoV-2 variants with increased transmissibility and potential resistance, antibodies and vaccines with broadly inhibitory activity are needed. Here wedeveloped a panel of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) that bound the receptor binding domain of the spike protein at distinct epitopes and blocked virusattachment to its host receptor, human angiotensin converting enzyme-2 (hACE2). Although several potently neutralizing mAbs protected K18-hACE2 transgenic mice against infection caused by ancestral SARS-CoV-2 strains, others induced escape variants in vivo or lost neutralizing activity against emerging strains. One mAb, SARS2-38, potently neutralized all SARS-CoV-2 variants of concern tested and protected mice against challenge by multiple SARS39 CoV-2 strains. Structural analysis showed that SARS2-38 engaged a conserved epitope proximal to the receptor binding motif. Thus, treatment with or induction of neutralizing antibodies that bind conserved spike epitopes may limit the loss of potency of therapies or vaccines against emerging SARS-CoV-2 variants."
PS: This team studied the Covid virus on mice and obtained 43 antibodies from them that recognize the RBD (receptor-binding domain). Then they selected nine of the most potent neutralizing antibodies and tested on mice to see whether they could protect animals infected with the original SARS-CoV-2 from disease. Multiple antibodies passed both tests, with varying degrees of potency.
Then they selected the two antibodies that were most effective at protecting mice from disease and tested them against a panel of viral variants. The panel comprised viruses with spike proteins representing all four variants of concern (alpha, beta, gamma and delta), two variants of interest (kappa and iota), and several unnamed variants that are being monitored as potential threats.
One antibody, SARS2-38, easily neutralized all the variants. Moreover, a humanized version of SARS2-38 protected mice against disease with all variants.
To conclude, Prof Michael S Diamond (Professor of Molecular Microbiology and of Pathology & Immunology.) says "This antibody is both highly neutralizing (meaning it works very well at low concentrations) and broadly neutralizing (meaning it works against all variants).
Also, it binds to a unique spot on the spike protein that isn't targeted by other antibodies under development. That's great for combination therapy. We could start thinking about combining this antibody with another one that binds somewhere else to create a combination therapy that would be very difficult for the virus to resist."
