Developing new treatments for COVID-19

01 June 2021
Key Researchers
Laboratory Head
Professor Wai-Hong Tham in a WEHI laboratory

WEHI researchers have shown antibodies from alpacas could hold the key to new COVID-19 treatments.

The research team identified ‘neutralising’ nanobodies that block SARS-CoV-2 – the virus that causes COVID-19 – from entering cells in preclinical models.

The consortium-led research effort brought together the expertise of leaders in infectious diseases and antibody therapeutics from WEHI, the Doherty Institute and the Kirby Institute.

WEHI infectious disease specialist Associate Professor Wai-Hong Tham, who led the research, said the discovery paved the way for further investigations into nanobody-based treatments for COVID-19.

“COVID-19 treatments are still essential for people who have not or cannot be vaccinated against COVID-19, people who are immunocompromised, and in people with severe disease.”
Associate Professor Wai-Hong Tham

“Antibodies are key infection fighting molecules in our immune system. They protect us by targeting and binding to specific proteins, such as those on the surface of viruses.

Antibody-based therapies, or ‘biologics’, harness this property of antibodies to block viruses from entering cells and remove them from the body.”

Visualisation of SARS-CoV-2 virus with nanobodies (purple) attaching to the virus ‘spike’ protein.
Visualisation of SARS-CoV-2 virus with nanobodies (purple) attaching to the virus ‘spike’ protein. Image: Dr Drew Berry in collaboration with Associate Professor Wai-Hong Tham

‘Nanobody cocktail’ offers potent solution

As part of the research, a group of alpacas in regional Victoria were given a synthetic, non-infectious part of the SARS-CoV-2 ‘spike’ protein, causing them to produce protective nanobodies. Nanobodies are tiny fragments of antibodies that are produced naturally by alpacas in response to infection.

“We can then extract the gene sequences encoding the nanobodies and use this to produce millions of types of nanobodies in the laboratory and select the ones that best bind to the spike protein.”
Associate Professor Wai-Hong Tham

“The leading nanobodies that blocked virus entry were then combined into a ‘nanobody cocktail’. By combining the two leading nanobodies, we were able to test its effectiveness at blocking SARSCoV-2 from entering cells and reducing viral loads in preclinical models.”

“In the wake of COVID-19, there is a lot of discussion about pandemic preparedness. Nanobodies that are able to bind to human coronaviruses – including SARS-CoV-2, SARS-CoV and MERS – could prove effective against future coronaviruses as well.”
Associate Professor Wai-Hong Tham
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