Neuroscientists isolate ‘mini-antibodies’ against COVID-19 in llamas


Published: 2020-12-28 12:02

Last Updated: 2021-02-28 01:51

Neuroscientists isolate ‘mini-antibodies’ against COVID-19 in llamas
Neuroscientists isolate ‘mini-antibodies’ against COVID-19 in llamas

On Dec. 22, a study led by US National Institute of Health (NIH) neuroscientists Thomas Esparza and David Brody identified a set of promising, mini antibodies against COVID-19 produced by a llama named Cormac.

Preliminary results suggested that at least one of these antibodies (NIH-CoVnb-112), could prevent infections and detect virus particles by grabbing hold of spike proteins found in COVID-19.

Additionally, these antibodies appeared to work well in either liquid or aerosol form, suggesting it could remain effective after entering lungs or during the inhalation process.

"For years [Thomas] and I had been testing out how to use [antibodies] to improve brain imaging. When the pandemic broke, we thought this was a once in a lifetime, all-hands-on-deck situation and joined the fight," said Brody.

He added, "we hope that these anti-COVID-19 nanobodies may be highly effective and versatile in combating the coronavirus pandemic."

According to Science Daily, a mini-antibody is a special type of antibody naturally produced by the immune systems of a certain group of animals including llamas and camels.

They are named the ‘mini-antibody’ due to their weight being about a tenth of the weight of human ones. Additionally, they can play a critical role in the immune system's defenses by recognizing proteins on viruses, bacteria, and other invaders, also known as antigens.

Since the beginning of the pandemic, many researchers have produced llama mini-antibodies against the infamous coronavirus spike protein that may prove to be effective at preventing COVID-19 infections. However, in the aforementioned study, Esparza and Brody used a slightly different strategy than others.

The spike protein acts like a key, said Esparza, adding that, the protein does this by opening ‘doors’ to infections when it binds to a protein called the angiotensin converting enzyme 2 receptor or ACE2 receptor, which is found on the surface of some cells.

"We developed a method that would isolate nanobodies that block infections by covering the teeth of the spike protein that bind to and unlock the ACE2 receptor,” said Esparza.

In order to make this possible, Esparza and Brody immunized the Llama five times over 28 days with a purified version of the spike protein. After testing hundreds of mini-antibodies, they found that the Llama produced 13 promising mini-antibody candidates.

According to Science Daily, initial experiments suggested that one candidate, called NIH-CoVnb-112, showed great potential. Test tube studies showed that this mini-antibody bound to the ACE2 receptor two to 10 times more than the mini-antibodies produced by other labs.

The research results showed that the NIH-CoVnB-112 mini-antibody could be effective at preventing coronavirus infections. To mimic the SARS-CoV-2 virus, the researchers genetically mutated a harmless virus so that it could use the spike protein to infect cells that have human ACE2 receptors. The researchers saw that relatively low infections were witnessed in the petri dishes with the presence of the mini-antibodies protecting the cells.

Importantly, the research showed that the mini-antibody was equally effective in preventing the infections in petri dishes when it was sprayed through an inhaler.

"One of the exciting things about antibodies is that, unlike most regular antibodies, they can be aerosolized and inhaled to coat the lungs and airways," said Brody.

The team has applied for a patent for the antibody.

"Although we have a lot more work ahead of us, these results represent a promising first step," said Esparza.