NIH Team Isolates Promising Llama Nanobody Against COVID-19
It has been thought that llamas may hold the key to developing an effective therapeutic against COVID-19, as well as the flu. This morning, scientists from the National Institutes of Health made additional headway in llama research, isolating promising antibodies from the South American animal.
NIH researchers isolated COVID-19 antibodies, which they called nanobodies, from a llama named Cormac. The study showed that one of the antibodies, called NIH-CoVnb-112, could prevent COVID-19 infections. Interestingly, the researchers determined the antibody worked equally well in either liquid or aerosol form, suggesting it could remain effective after inhalation. The data was published in the journal Scientific Results.
Nanobodies are a special type of antibody that are naturally produced by llamas and other camelids. They are smaller than typical antibodies found in a human. The researchers said the nanobodies are “free-floating versions of the tips of the arms of heavy chain proteins, which form the backbone of a typical Y-shaped human IgG antibody.” Those tips play an important role in the immune response.
The NIH study was led by two neuroscientists, Thomas J. “T.J.” Esparza, and David L. Brody, both of whom work in the NIH’s National Institute of Neurological Disorders and Stroke. Esparza and Brody are not the first scientists to look at the llama antibodies as a potential COVID-19 treatment. Researchers from the Vlaams Institute for Biotechnology in Ghent, as well as the University of Texas at Austin examined the antibodies for a potential treatment against COVID-19. Additionally, researchers at the University of California at San Francisco synthesized llama nanobodies, which in early research, showed an effective ability to bind to the spike proteins of COVID-19. Also, researchers in the United Kingdom took a similar approach. Scientists from the U.K.’s Rosalind Franklin Institute told BioSpace earlier this year they intended to take this study into human trials.
In the NIH study, the researchers follow a slightly different strategy to find the nanobodies. The nanobodies bind to the angiotensin converting enzyme 2 (ACE2) receptor before they can enter the cells. Esparza said he and his partner “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.” Following an intensive study of Cormac, the research team found the llama produced 13 nanobodies that might be strong candidates against COVID-19. From that set of 13, they settled on NIH-CoVnb-112. The research found that particular antibody “bound to the ACE2 receptor 2 to 10 times stronger than nanobodies produced by other labs.” Additional experiments showed the nanobody stuck directly to the ACE2 receptor binding portion of the spike protein, the NIH said.
The team found the nanobody was effective in both aerosol form and as a liquid. The NIH team applied for a patent on the NIH-CoVnB-112 nanobody and aims to study it further.
“Although we have a lot more work ahead of us, these results represent a promising first step,” Esparza said in a statement. “With support from the NIH we are quickly moving forward to test whether these nanobodies could be safe and effective preventative treatments for COVID-19. Collaborators are also working to find out whether they could be used for inexpensive and accurate testing.”