BREAKTHROUGH! Scientists discover Llama antibodies that can fight COVID and its future variants

Scientists have unearthed a rare class of ultra-potent antibodies derived from llamas that can neutralize a vast array of coronaviruses—including SARS-CoV-1 and multiple forms of SARS-CoV-2, both old and new.

Scientists discover llama antibodies that shut down COVID

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In a major breakthrough, scientists have unearthed a rare class of ultra-potent antibodies derived from llamas that can neutralize a wide range of coronaviruses—including SARS-CoV-1 and multiple forms of SARS-CoV-2, both old and new. These tiny antibodies, published in Nature Communications, home in on a deeply buried and conserved region at the base of the virus’s spike protein, effectively “locking” the virus shut and rendering it incapable of infecting cells.

With COVID-19 still evolving into new and more elusive variants, existing antibody treatments are rapidly losing their effectiveness. This challenge arises because most antibody therapies focus on parts of the virus—like the receptor-binding domain—that mutate frequently to dodge immune detection.

To counter this problem, a team led by Professor Xavier Saelens and Dr. Bert Schepens at the VIB-UGent Center for Medical Biotechnology focused on the S2 subunit of the spike protein, a critical component in the virus's fusion mechanism with human cells and one of the most stable structures across coronavirus families.

A molecular clamp on the virus

Enter Winter, a llama with a secret weapon. Unlike humans, llamas produce ultra-small antibodies—called single-domain antibodies or nanobodies—that can access regions on the virus that are otherwise hidden from conventional antibodies. From Winter’s immune system, the team isolated several nanobodies capable of neutralizing a wide spectrum of SARS-related viruses.

What makes these nanobodies extraordinary is not just their range, but their method. They clamp down on a specific three-helix bundle at the base of the spike protein—a structure vital for the virus’s transformation and cell entry. By freezing the spike protein in its original shape, the nanobodies prevent it from transitioning into the infection-ready form.

A fortress the virus can't breach

These llama-derived antibodies showed robust protection in animal studies—even in minimal doses. And when researchers attempted to provoke viral escape by repeatedly challenging the virus, it yielded only rare and significantly weakened variants.

"This region is so crucial to the virus that it can't easily mutate without weakening the virus itself," explains Schepens, senior author of the study. “That gives us a rare advantage: a target that's both essential and stable across variants.”

This remarkable discovery signals a major leap forward in antiviral therapy. It offers the tantalizing possibility of long-lasting treatments that remain effective even as the virus continues to mutate.

"The combination of high potency, broad activity against numerous viral variants, and a high barrier to resistance is incredibly promising," adds Saelens. "This work provides a strong foundation for developing next-generation antibodies that could be vital in combating not only current but also future coronavirus threats."