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Washington, November 6
Scientists have found a new method to extract small but extremely potent new coronavirus antibody fragments from llamas, which they believe could be modeled into inhalable therapies with the potential to prevent and treat COVID-19.
These special llama antibodies, called nanobodies, are much smaller than human antibodies, according to researchers at the University of Pittsburgh School of Medicine in the United States.
They are many times more effective in neutralizing the SARS-CoV-2 virus, which causes COVID-19, and are also much more stable, they said.
“Nature is our best inventor,” said Yi Shi, senior author of the study published Thursday in the journal Science.
“The technology we have developed examines SARS-CoV-2 neutralizing nanobodies on an unprecedented scale, which has enabled us to rapidly discover thousands of nanobodies with unrivaled affinity and specificity,” said Shi.
The researchers immunized a black llama named Wally with a piece of the SARS-CoV-2 spike protein, and after about two months, the animal’s immune system produced mature nanobodies against the virus.
Using a mass spectrometry-based technique, study lead author Yufei Xiang, a research assistant in Shi’s lab, identified the nanobodies in Wally’s blood that bind to SARS-CoV-2 most strongly.
The scientists then exposed their nanobodies to the live SARS-CoV-2 virus and found that just a fraction of a nanogram could neutralize enough virus to spare a million cells from infection.
These nanobodies represent some of the most effective therapeutic antibody candidates for SARS-CoV-2, hundreds to thousands of times more effective than other llama nanobodies discovered through the same phage display methods used for decades to fish for human monoclonal antibodies, they said. researchers.
The nanobodies can stay at room temperature for six weeks and tolerate being turned into an inhalable mist to deliver antiviral therapy directly into the lungs where they are needed most, they said.
Since SARS-CoV-2 is a respiratory virus, nanobodies could find and attach to it in the respiratory system, even before it has a chance to do any damage.
Traditional SARS-CoV-2 antibodies require a drip, which dilutes the product throughout the body, requiring a much larger dose and costing patients and insurers about $ 100,000 per course of treatment.
“The nanobodies could potentially cost much less. They are ideal for addressing the urgency and scale of the current crisis,” Shi said.
In collaboration with researchers from the Hebrew University of Jerusalem, the team found that their nanobodies use a variety of mechanisms to block SARS-CoV-2 infection.
This makes the nanobodies ripe for bioengineering, the researchers said.
For example, nanobodies that bind to different regions of the SARS-CoV-2 virus can be linked together, like a Swiss Army knife, in the event that part of the virus mutates and becomes drug resistant, they said. PTI
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