Winter is a lama grazing peacefully in the meadows near the city of Ghent in Belgium. The young camelid could also play a key role in the search for a new animal. treatments for Covid-19.
Indeed, Winter has been immunised with a infusion containing proteins surface protein (protein S) of two coronavirus the Mers-CoV and the Sars-CoV-1. Scientists have identified the plasma du lama des petits antibodies neutralising agents that proved effective against two pseudotyped viral particles (a lentivirus modified to express coronavirus surface proteins) mimicking the two strains of coronavirus against which Winter has been immunised, as well as the Sars-CoV-2.
The results of this study will be published in the journal Cell. A preliminary, peer-reviewed version is available from already available.
Small neutralising antibodies
These particular antibodies are a subclass of camelid-specific IgG called VHH. They have only one heavy chain, whereas conventional IgGs have a light chain and a heavy chain. VHHs therefore have only one variable domain, located on the heavy chain.
Crystallographic analysis was used to determine which part of the virus reconstituted HHV from Winter's plasma bind: the receptor binding domain (RBD) of protein S. Several studies have demonstrated their neutralising action against Sars-CoV-1 and Mers-CoV in cell cultures in vitro. One of them, VHH-72, is capable of neutralising infection by the viral pseudoparticle mimicking Sars-CoV-1, as well as that mimicking Sars-CoV-2.
Smaller than conventional IgGs, VHHs are stable and could be administered via a spray to be inhaled, in particular to treat respiratory infections. Scientists hope that the neutralising capacity of llama HHVs makes them serious candidates for treating Covid-19.
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