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November 6, 2020 12:03:26 pm
FILE – In this May 2020 file photo provided by Eli Lilly, a researcher tests for possible COVID-19 antibodies in a laboratory in Indianapolis. (David Morrison / Eli Lilly via AP, file)
Scientists have found a new method to extract small but extremely powerful antibody fragments to the new coronavirus from flames, which they say could be turned into inhalable therapies with the potential to prevent and treat COVID-19.
These special flame 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 at neutralizing the SARS-CoV-2 virus, which causes COVID-19, and they are also much more stable, they said.
“Nature is our best inventor,” said Yi Shi, lead author of the study published in the journal Science on Thursday.
“The technology we developed examines SARS-CoV-2 neutralizing nanobodies on an unprecedented scale, allowing us to rapidly discover thousands of nanobodies with unmatched affinity and specificity,” Shi said.
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 technique based on mass spectrometry, the study’s lead author, Yufei Xiang, a research assistant in Shi’s lab, identified the nanobodies in Wally’s blood that bind 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 prevent a million cells from becoming infected.
These nanobodies represent some of the most effective therapeutic antibody candidates for SARS-CoV-2, hundreds to thousands of times more effective than other flame nanobodies discovered through the same phage display methods used for decades to fish for monoclonal antibodies. humans, the researchers said.
The nanobodies can stay at room temperature for six weeks and tolerate turning into an inhalable mist to deliver antiviral therapy directly to the lungs where they are needed most, they said.
Since SARS-CoV-2 is a respiratory virus, nanobodies could find it and stick to it in the respiratory system, even before it has a chance to cause harm.
Traditional antibodies to SARS-CoV-2 require an intravenous line, which dilutes the product throughout the body, requiring a much higher dose and costing patients and insurers around $ 100,000 per course of treatment.
“Nanobodies could potentially cost a lot less. They are ideal for addressing the urgency and magnitude of the current crisis, ”Shi said.
In collaboration with researchers from the Hebrew University of Jerusalem, the team discovered that their nanobodies use a variety of mechanisms to block SARS-CoV-2 infection.
This makes the nanobodies ready for bioengineering, the researchers said.
For example, nanobodies that bind to different regions of the SARS-CoV-2 virus can bind, like a Swiss army knife, in case a part of the virus mutates and becomes resistant to drugs, they said.
