Immune particles from llama blood may provide protection against some COVID-19 mutants

Researchers led by Mount Sinai found that small, tough immune particles from llama blood include all COVID-19 variants, including Omicron, and 18 similar, including SARS-CoV-2 and SARS-CoV-1. It was the cause of the outbreak of SARS in 2003, which showed that it could provide strong protection against the virus.

study: Superimmunity by pansalvecovirus nanobody.. Image Credit: Rita_Kochmarjova / Shutterstock

In the paper published in Cell report On June 28, the team announced that these “superimmune” molecules, known as nanobodies, could be stored and used worldwide against evolving pandemics and future viruses, with immediate inhalation. It suggests that it may be a precursor to antiviral treatment or spraying.

Compared to other animal kingdoms, llamas, camels and alpaca have a unique immune system. They produce antibodies with one polypeptide chain instead of two.

This construct yields an antibody that is about one-tenth the size of a normal antibody, is very stable, and can bind tightly to the target of the disease. These unique properties allow researchers to easily link multiple Nanobodies like a daisy chain. Therefore, if a virus attempts to escape by mutation, another Nanobody is ready to continue to suppress it.

Due to their small size and wide neutralizing effect, these Camelid Nanobodies may be effective against future variants and outbreaks of viruses such as SARS. Their excellent stability, low manufacturing cost, and ability to protect both the upper and lower respiratory tracts from infection complement vaccines and monoclonal antibody drugs with new COVID-19 variants or SARS-CoV-. It means that we can provide important treatments. 3 will appear.“”

Yi Shi, PhD, Principal Writer and Associate Professor of Pharmacology, Director of the Center for Protein Engineering and Therapeutics at Mount Sinai School of Medicine

As an important part of their study, Dr. Shi’s team immunized a llama named “Wally” with the SARS-CoV-2 receptor binding domain (RBD). It is a short fragment or spike of the virus that invades the surface of human cells and spreads the infection. They found that repeated immunization with RBD produced Nanobodies that recognized Wally not only the COVID-19-causing virus SARS-CoV-2, but also a vast number of other coronaviruses. .. From this discovery, the team isolated and validated a large repertoire of highly potent antiviral nanobodies that are effective against a broad spectrum of viruses such as SARS.

“We learned that the small size of these nanobodies has a decisive advantage over rapidly changing viruses,” said co-author Ian Wilson, PhD, Professor Hansen of Structural Biology, and Scripps Research’s integrated structure. And the chair of the Computational Biology Division explains. In La Jolla, California. “Specifically, it invades dents, corners, and crevices on the surface of the virus and binds to multiple areas to prevent the virus from escaping or mutating.”

From this structural information, the team designed an ultra-strong Nanobody that can simultaneously bind to two regions of the SARS-like virus on the RBD and prevent mutation avoidance. The resulting molecule (PiN-31) is very stable and can be used as an aerosolized form for inhalation therapy or spray. This is valid for SARS-CoV-2, as the same team showed in previous studies.

“We need more research, but we believe that the wide range of protection and ultra-strong Nanobodies that we have separated in our labs can be used for human use,” said Dr. Ichi, who previously conducted most of the research at the University of Pittsburgh. Says. Moved his lab to Icahn Mount Sinai. By enhancing the appeal of this potential treatment, these highly versatile antivirals can be rapidly produced virtually anywhere from microorganisms such as: E. coli Or yeast cells, he adds. In the past, Nanobody therapies have been clinically proven to be safe and effective against human illnesses such as blood coagulopathy and cancer.

“To win the battle between current pandemics and future viral outbreaks, we need to quickly develop and equitably distribute weapons of cost-effective and convenient technology,” Dr. Shi emphasizes. “The new, inhalable and highly potent Nanobodies we have discovered can meet their global demand, especially in developing countries where they are most vulnerable to viruses and there is no cure for them. I strongly believe that I can do it. “