Of the 19 types of antibodies, peptiluvimab was the only one effective against the three sub-variants
Color scanning electron microscopy of cells (blue) infected with SARS-CoV-2 virus particles (red), isolated from a patient sample. The photo was taken at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland, USA. Credit: NIAID
The omicron mutant has been known to spread widely, causing the largest ever increase in COVID-19 cases. To date, researchers have identified three most common omicron variants or substrains that share 21 mutations in the hashish protein - or "protein S" - that make up the spines. They are known as BA.1, BA.1.1, and BA.2.
When the omicron mutant first appeared in November 2021, the dominant sub-strain was the BA.1 omicron, and it remained so until December, when BA.1 cases began to decline, while cases of BA1.1 - which differ from the BA.1 strain by having An additional mutation called R346K—currently accounts for approximately 40% of omicron cases globally, 35-60% of cases in New Zealand, the United Kingdom and the USA, and substrain BA.2 only accounts for about 10% of cases However, it is the dominant breed in Denmark, India and South Africa.
Last month, the US Food and Drug Administration (FDA) authorized the emergency use of beptelovimab to treat COVID-19 infection, and bebtelovimab is a monoclonal antibody.
In this context, a recent study published in the journal Nature reported the efficacy of the drug against the three sub-variants of Omicron, and the study concluded that the efficacy of mRNA vaccines and other antibody treatments against the three sub-variants was diminished.
The researchers - from American Columbia University and the Chinese University of Hong Kong - conducted laboratory experiments that included 19 monoclonal antibodies, and also investigated the sensitivity of sub-strains of Omicron to neutralization by antibodies obtained from individuals who had previously been infected with the SARS-CoV-2 virus, and those who received the Pfizer and Moderna vaccines, as well as those who received a booster dose of the vaccine.
the only winner
Of the 19 antibodies studied, the researchers found that only one type was able to neutralize all three sub-mutants of the omicron variant, and this type represented the recently approved FDA-approved peptiluvimab.
The authors also found that the BA.2 substrain showed significant resistance to 17 antibodies, including a 27-fold decrease in the activity of sutrovimab, an antibody that has a strong effect against other substrains, and cilgavimab. It was effective against BA.2 substrain, but had no effect against BA.1, while the last antibody “peptiluvimab” retained a strong effect against the three omicron substrains.
Florian Kramer, Professor of Vaccines in the Department of Microbiology at the American Mount Sinai School of Medicine, praised the importance of the study, and indicated that it was conducted well, as he said in his interview with “For Science”: “The study highlights the presence of sub-variables of the Omicron mutant, and that no We need to keep that in mind and not just focus on the first mutant version of Omicron BA.1."
Virus neutralization
The immune system can eliminate infectious particles before they can cause an infection, which is known in immunology as "neutralization."
The neutralization process occurs through certain antibodies produced by the body as part of a specialized or adaptive immune response. Antibodies bind to specific parts of the virus known as epitopes, and work to prevent viral infection in several ways, including preventing viruses from binding to receptors that enable them to Entering cells and causing infection, as well as preventing the virus from starting its reproduction cycle and producing its proteins.
Hana Al-Sahli, a professor of molecular virology, microbiology and infectious diseases at Baylor College of Medicine, who was not involved in the study, said in her interview with Al-Alam: “Neutralizing the virus is one of the functions of antibodies, whether they are monoclonal - targeting one part of the protein - Like the ones we use as therapy, or polyclonal antibodies - they target different parts of the virus proteins like those from infection, however, monoclonal antibodies can quickly lose their function if the virus mutates, which viruses constantly do.”
Monoclonal antibodies are produced from a single B immune cell, while multiple immune cells participate in the production of polyclonal antibodies, Kramer adds: “Monoclonal antibodies isolated from patients are currently used as a treatment, or even for prevention, against "SARS-Cove-2 virus, and there is disagreement among scientists about the effectiveness of antibodies against omicron sub-variants, but through some experiments we found that there is a significant loss in the ability of antibodies to neutralize omicron sub-mutants, which explains the wide spread of infections." Monoclonal antibodies are also made in a laboratory.
Al-Sahli explained that the current study is an extension of the results of a previous study conducted by the same research team, which indicated the low ability of sera - whether extracted from infected people or those who received vaccines - to neutralize the omicron mutant and its sub-variables.
David Hu - Professor of Microbiology and Immunology, Director of the Aaron Diamond Center for AIDS Research at Columbia University, and the author of the study - said in a press release published last December about their previous study: "It is possible that (SARS-Cove-2)" One or two mutations away from becoming fully resistant to current antibodies, whether monoclonal antibodies used as therapeutics or antibodies resulting from vaccination or infection with previous variants of the virus.
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