Llama inspired “AeroNabs” to strangle COVID-19 with an inhaler
Reporter : Irina Robu, PhD
Llama and other camelids fight off pathogens like viruses with tiny antibodies called nanobodies. A USCF team used protein engineering to make a synthetic nanobody that prevents the spike protein on the surface of SARS-CoV-2 from binding to healthy cells and infecting them. The team indicates promising preclinical results for aerosol formulation and can be used as a self-administered form of protein against the virus.
According to the UCSF team, an aerosolized form of nanobody exhibit SARS-CoV-2 incapable of binding to the ACE2 receptor on healthy cells that line airways. The synthetic nanobody stays functional after it was freeze-dried, exposed to heat and aerosolized.
The researchers ongoing screening a library of synthetic nanobodies, ultimately landing on 21 that banned the spike-ACE2 interaction. The scientists decided that in order to be truly efficient, a nanobody based treatment with interact with all three of the receptor binding domains on the spike protein that attaches to ACE2. Their solution was to engineer a molecular chain that connects three nanobodies together, which would ensure that when one of the nanobodies attached to RBD, the others would link to the two remaining RBD. This molecular chain resulted in a drug candidate proved to be 200,000 times more potent than a single antibody.
At the same time, ExeVir Bio is also developing an aerosolized COVID-19 treatment inspired by llamas and is currently trying to advance its candidate into clinical trials by the end of the year. Their main candidate, VHH-72Fc was considered to bind to an epitope that is found both in SARS-CoV-2 and SARS-CoV. Yet, the llama inspired treatments are still behind antibody efforts like that of Regeneron.
Even though, there are multiple vaccines in development, researchers at UCSF believe that AeroNabs can be used as a sort of personal protective equipment until vaccines become available. The same researchers are planning human trials and are in discussion with partners who can provide manufacturing and distribution backing.
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