TORONTO -- An alpaca’s bloodstream may seem like an unlikely place to search for a COVID-19 treatment, but Swedish researchers say their unusual approach has uncovered a minuscule antibody with the ability to block the coronavirus from entering human cells.
The findings, published Friday in the journal Nature Communications, come after months of research on a 12-year-old alpaca in Germany named Tyson.
In February, researchers from the Karolinska Institute, a medical university based in Solna, Sweden, injected Tyson with coronavirus spike proteins and, once an immune response was detected, took samples of antibody-rich blood from the animal.
Alpacas and other members of the camel family have long been used in viral research because they naturally produce nanobodies, tiny fragments of antibodies that can be adapted for humans. Researchers have turned to llamas and alpacas in the past when studying HIV, SARS and MERS.
These nanobodies are able to penetrate hard-to-reach areas on spike proteins, which allow viruses, like the novel coronavirus, to enter human cells and infect them.
Nanobodies from the camel family, which can also be produced in sharks, have been shown to block virus proteins more effectively than humans’ larger antibodies.
After months of research, the Swedish researchers found what they were hoping for: a nanobody that they say “efficiently neutralizes the virus” by attaching itself to a specific part of the virus protein that can block the virus from "slipping into the cells and thus prevents infection.”
They’ve dubbed the nanobody Ty1, in honour of Tyson.
"Our results show that Ty1 can bind potently to the SARS-CoV-2 spike protein and neutralize the virus, with no detectable off-target activity" said Ben Murrell, co-senior author of the publication.
The next steps are for researchers to begin preclinical animal studies to investigate the therapeutic potential of the nanobody. They hope that, eventually, Ty1 could be harnessed as a treatment, not a vaccine, against the virus.
“We hope our findings can contribute to the amelioration of the COVID-19 pandemic by encouraging further examination of this nanobody as a therapeutic candidate against this viral infection," said corresponding author Gerald McInerney in a statement.
Separate research on a llama named Winter living in the Belgian countryside has also offered interesting insights. In May, researchers studying Winter’s reaction to the coronavirus released preliminary findings in which they were able to engineer a new antibody. This new antibody was able to tightly bind to the spike protein on the surface of the new coronavirus to block it from infecting cells in culture.
But some researchers have raised doubts about studies on alpacas and llamas. Earlier this year, Brian Lichty, a virologist at McMaster University in Hamilton, Ont., told CTVNews.ca that the nanobodies in question only block “one point of entry” for the virus, and doesn’t account for other receptors.
Lichty added that it will take a “cocktail” of different antibodies that would be able to bind on to several different places on the spike protein to prevent it from entering human cells.
With files from CTVNews.ca's Jackie Dunham
