- Researchers from the University of Pittsburgh School of Medicine identified a llama antibody that can block the novel coronavirus from infecting cells.
- The nanobodies are extremely efficient at neutralizing the spike protein of the virus, according to the study.
- A compound based on llama antibodies could be used in an inhaler to send those nanobodies deep into the lungs of COVID-19 patients and block the virus from doing more damage.
Llamas and other camelids might help scientists develop powerful coronavirus drugs that could treat COVID-19 patients. The first such tests were performed early in the pandemic, with researchers looking at llama antibodies for creating monoclonal antibody drugs that would work inside human hosts. These are similar to human antibodies that the immune system produces upon infection with a pathogen like SARS-CoV-2. Some of those antibodies are called neutralizing antibodies because they can block the virus from binding to cells. Without the ability to infect cells, the virus can’t replicate itself and it’s eventually killed off. The lower the quantity of the virus inside the body, the lower the intensity of symptoms and the faster the recovery.
Potent antibodies can be turned into monoclonal antibody drugs that will boost the defense of COVID-19 patients and maybe even provide some limited immunity. But monoclonal antibody treatment will not work on all patients, as recent data has shown. Moreover, the treatment requires hospitalization because the monoclonal antibodies are administered intravenously. At least, we thought that would be the case.
Researchers who are studying promising llama-derived antibodies think they made a breakthrough discovery. Llamas can develop nanobodies, or tinier antibodies, that are very stable and very efficient at blocking the virus. Antibody drugs derived from these nanobodies could treat patients at home via an inhaled spray that would pulverize the coronavirus inside the lungs.
The novel coronavirus binds efficiently to ACE2 receptors in the lungs. This explains the cough and breathing issues that appear during COVID-19, as well as the various respiratory complications that can lead to severe illness and death.
Scientists at the University of Pittsburgh School of Medicine (UPSM) published a paper in Science describing the powerful nanobodies they’re researching. They infected a llama with a piece of SARS-CoV-2’s spike protein, which acts as a key for the virus and allows it to gain entry into healthy cells. After 50-55 days, they analyzed the antibodies the llama produced using a mass spectrometry technology.
They found nanobodies inside the llama’s blood, which are even smaller and more stable than regular antibodies. They discovered that a fraction of a nanogram of nanobodies would be enough to neutralize a quantity of virus that would otherwise infect a million cells.
The nanobodies can survive at room temperature for six weeks, and they can be used inside inhalers. This would allow the drug to act directly where the virus spreads and provide immediate protection.
Before the llama nanobodies can be turned into a COVID-19 medicine, they’ll need to show efficacy and safety in clinical trials. Regeneron and Eli Lilly have already applied for emergency use authorizations for their monoclonal antibody drugs, as some of their clinical trials showed that the drugs could help patients. President Trump got an infusion with the Regeneron test candidate during his COVID-19 therapy. The FDA has already approved blood plasma treatment for COVID-19, allowing doctors to treat patients with antibodies from people who recovered from the illness. These antibody-based therapies have some limitations, but they prove that great progress has been made when it comes to coronavirus antibodies. Hopefully, llama nanobodies will work just as well or even better.
Separately, researchers from the University of California San Francisco’s AeroNabs created a nanoparticle inspired by llama nanobodies. They’ve also adapted the drug to be used inside an inhaler.
A clip from the UPMC describing their progress with llama nanobodies follows below, with the full study available at this link.