Scientists have developed a set of promising, tiny antibodies or nanobodies that counteract the novel coronavirus from llamas, some of which could prevent the infection.
Preliminary findings, published in the journal Scientific Reports, indicate that the nanobody appears to function equally well in liquid or aerosol form, suggesting that it may remain effective after inhalation. .
The researchers from the National Institutes of Health (NIH) in the U.S. said that at least one of these nanobodies, called NIH-CoVnb-112, could prevent infections and detect virus particles by catching on the spike proteins of SARS-CoV-2, which induces Covid-19.
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“We hope these anti-Covid-19 nanobodies could be very effective and multifunctional in fighting the coronavirus pandemic,” said David L. Brody, who is also a professor at University of Uniformed Services for the Health Sciences.
A nanobody is a special type of antibody produced naturally by the immune systems of camelids, a group of animals that include camels, llamas, and alpacas.
On average, these proteins are around the tenth weight in most human antibodies, the researchers said.
This is because isolated nanobodies in the laboratory are largely free versions of heavy-chain protein arm proliferations, which are the backbone of human-shaped IgG antibody, they said.
These suggestions play a vital role in protecting the immune system by identifying proteins on viruses, bacteria, and other invaders, also known as antigens.
Because nanobodies are more stable, cheaper to produce, and easier to invent than conventional antibodies, a growing group of researchers have been using them for medical research.
Read also: Novel inhalable llama antibodies may help treat, prevent Covid-19: A study
Since the outbreak of the pandemic, several researchers have developed llama nanobodies against the SARS-CoV-2 spike protein that may be effective in preventing disease.
In the most recent study, the researchers used a slightly different strategy than the others to find nanobodies that could work particularly well.
“The spike protein SARS-CoV-2 acts as a key. It does this by opening the door to disease when it binds to a protein called the angiotensin receptor that converts enzyme 2 (ACE2), which is found on the surface of some cells, “said Thomas J Esparza, lead author of the study.
“We developed a method that would separate nanobodies that prevent infections by covering the teeth of the spike-binding protein and releasing the ACE2 receptor,” Esparza said.
The researchers administered a llama vaccine called Cormac five times over 28 days with a pure version of SARS-CoV-2 spike protein.
After testing hundreds of nanobodies, they discovered that Cormac produced 13 nanobodies that could be strong contenders.
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Initial tests suggested that a single candidate, called NIH-CoVnb-112, could work well, the researchers said.
Test tube studies showed that this nanobody attached to the ACE2 receptor was 2 to 10 times stronger than nanobodies produced by other laboratories, they said.
Other experiments suggested that the NIH nanobody would directly bind to the ACE2 receptor binding component of the spike protein.
The team then showed that the nanobody NIH-CoVnB-112 could be effective in preventing coronavirus infections.
To report the SARS-CoV-2 virus, the researchers genetically modified a harmless “pseudovirus” to use the spike protein to capture cells containing human ACE2 receptors.
The researchers found that relatively low levels of NIH-CoVnb-112 nanobodies prevented the pseudovirus from taking up these cells in petri vessels.
They showed that the nanobody was just as effective in preventing infections in petri dishes when sprayed through the nebuliser, or inhaler type, often used to treat patients with asthma. .