Mini antibodies against COVID-19 isolated from llama may prevent infection
Scientists have isolated a set of promising, tiny antibodies or nanobodies against the novel coronavirus from a llama, some of which may help prevent the infection. Preliminary results, published in the journal Scientific Reports, suggest that the nanobody appears to work equally well in either liquid or aerosol form, suggesting it could remain effective after inhalation.
What is a nanobody?
A nanobody is a special type of antibody naturally produced by the immune systems of camelids, a group of animals that includes camels, llamas, and alpacas.
What did the researchers say?
The researchers from the National Institutes of Health (NIH) in the US said at least one of these nanobodies, called NIH-CoVnb-112, could prevent infections and detect virus particles by grabbing hold of the spike proteins of SARS-CoV-2, which causes COVID-19. "We hope that these anti-COVID-19 nanobodies may be highly effective and versatile in combating the coronavirus pandemic," said professor David L. Brody.
Researchers used a different strategy to find nanobodies
The researchers immunized a llama called Cormac five times over 28 days with a purified version of the SARS-CoV-2 spike protein. After testing hundreds of nanobodies, they found that Cormac produced 13 nanobodies that might be strong candidates. Initial experiments suggested, one candidate, called NIH-CoVnb-112 could work, the researchers said. Nanobody bound to the ACE2 receptor is 2 to 10 times stronger than others.
'The SARS-CoV-2 spike protein acts like a key'
"The SARS-CoV-2 spike protein acts as a key. It does this by opening the door to infections when it binds to a protein called the Angiotensin-Converting Enzyme 2 (ACE2) receptor, found on the surface of some cells," said Thomas J Esparza, the lead author.
Nanobodies are also effective in preventing infections in petri dishes
The team then showed that the NIH-CoVnB-112 nanobody could be effective at preventing coronavirus infections. To mimic the SARS-CoV-2 virus, the researchers genetically mutated a harmless "pseudovirus" so that it could use the spike protein to infect cells that have human ACE2 receptors. The researchers saw that relatively low levels of the NIH-CoVnb-112 nanobodies prevented the pseudovirus from infecting these cells in petri dishes.
