Researchers at Karolinska Institute in Sweden have identified a small neutralizing antibody, ‘nanobody’ of sorts that can block the novel coronavirus from entering human cells.

The nanobodies have the capacity to block SARS-CoV-2, the virus that has caused the COvid-19 pandemic, from entering human cells. The results of the study have been published in the journal Nature Communications.

The nanobodies occur naturally in camelids and can be adapted for humans. Researchers injected an alpaca with the coronavirus spike protein to identify the small antibodies.

The tests results

The blood samples of the alpaca showed a strong immune response against the virus within sixty days. Researchers then studied the animal’s blood samples to identify and isolate the nanobody that can prevent infection. They identified a small antibody called ‘Ty1’, named after the alpaca Tyson, that “efficiently neutralizes the virus by attaching itself to the part of the spike protein that binds to the receptor ACE2, which is used by SARS-CoV-2 to infect cells.”

"Using cryo-electron microscopy, we were able to see how the nanobody binds to the viral spike at an epitope which overlaps with the cellular receptor ACE2-binding site, providing a structural understanding for the potent neutralisation activity," said Leo Hanke, a postdoc in the McInerney group and first author of the study.

These antibodies are easier to produce cost-effectively at scale according to the researchers. The team will now conduct more animal studies to better understand the efficacy and use of these antibodies in therapeutics for Covid-19 treatment.

Ben Murrell, assistant professor in the Department of Microbiology, Tumor and Cell Biology and co-senior author of the publication said, "We are now embarking on preclinical animal studies to investigate the neutralizing activity and therapeutic potential of Ty1 in vivo."

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