Nasal spray could prevent people from catching the coronavirus and be more effective than wearing PPE, scientists claim.

A nasal spray may prevent humans from contracting Covid-19 and could even be more effective than wearing Personal Protective Equipment (PPE), scientists claim. 

Scientists at the University of California, San Francisco created ‘AeroNabs,’ which contain nanobodies, antibody-like immune proteins found in the blood of llamas, camels, and alpacas. 

AeroNabs can be inhaled and may prove to be a short-term tool in preventing thousands of people from becoming infected with Covid-19 before a vaccine is eventually developed. The nanobodies in the formula are synthetic and have been engineered to target SARS-CoV-2, the virus behind the pandemic. While lab tests have shown that the tiny proteins — about a quarter of the size of antibodies found in humans — can block the coronavirus from entering cells, the AeroNabs formula still needs to be proven in clinical trials.

Dr. Peter Walter, a professor of biochemistry and biophysics at UCSF and AeroNabs co-inventor, said, “Far more effective than wearable forms of personal protective equipment, we think of AeroNabs as a molecular form of PPE that could serve as an important stopgap until vaccines provide a more permanent solution to Covid-19. For those who cannot access or don’t respond to SARS-CoV-2 vaccines, AeroNabs could be a more permanent line of defense.”  

Nanobodies, which were originally discovered in a Belgian lab in the late 1980s and have intrigued scientists globally ever since, have proven to work against similar coronaviruses in the past, including the one that causes Severe Acute Respiratory Syndrome (SARS). They are similar to human antibodies, which are immune proteins produced by the body in response to a pathogen, latching on to the pathogen and either tagging it for other immune cells or disabling it themselves. But nanobodies have a number of unique advantages for medicines, said AeroNabs co-inventor Dr. Aashish Manglik: nanobodies are much smaller, so they are easier to manipulate, modify in the lab and gear towards attacking viruses.  

The researchers, led by graduate student Michael Schoof, engineered a completely synthetic molecule based on nanobodies. Their findings are published in a paper on the preprint server bioRxiv, meaning it has not yet been reviewed by other scientists. 

The science: SARS-CoV-2 is covered in spikes that are used to infect human cells. The spikes attach to ACE-2 receptors found on the surface of human cells, including those that line the nasal passageway, lungs, and airways. ACE-2 receptors act as a doorway for the virus to enter cells, and the researchers essentially want to block that doorway.  

The team eventually selected 21 synthetic nanobodies that bounded to the spikes of the coronavirus and blocked the ACE-2 interaction. In further experiments, Dr. Veronica Rezelj, a virologist at Institut Pasteur in Paris, tested the three most promising nanobodies against the SARS-CoV-2, finding those nanobodies to be ‘extraordinarily potent, preventing infection even at extremely low doses.’ The most potent nanobodies not only act as a sheath but also as a ‘mousetrap,’ clamping down on the virus’s spikes when it is in an inactive state so that it cannot open up again. The scientists then engineered this nanobody to create two more genetically similar ones, using the three, which proved to be 200,000 times more potent than a single nanobody alone, to make AeroNabs. Professor Walter said its results against SARS-Cov-2 were ‘off the charts’.

“It was so effective that it exceeded our ability to measure its potency,” he claimed. 

The researchers still need to demonstrate that the synthetic nanobodies, and AeroNabs, could prevent the real virus from infecting cells.  

At the Rosalind Franklin Institute at Oxford University, scientists have been conducting early research using llama nanobodies, hoping that the llama-derived proteins can eventually be developed as a treatment for humans struck down with a severe case of Covid-19. Some experts say it could be used like convalescent serum therapy, which is when the antibody-rich blood of a Covid-19 survivor is injected into a patient.

But AeroNabs, the creators say, does not need to be injected and can be delivered directly to the lungs and or nasal passages. 

And to a lot of people who may be a vaccine and/or injection phobic, this news should come as a huge shot in the arm.

Reference: Daily Mail Article 13 August 2020