Science: Omicron mutant strains are evolving new ways to evade antibodies and vaccines.

Science: Omicron mutant strains are evolving new ways to evade antibodies and vaccines

With the large-scale epidemic of the virus, new virus mutant strains continue to appear, Alpha, Beta, Gamma, Delta, Omicron, etc.

The most concerned one in the world is undoubtedly the Omicron mutant strain

The Omicron mutant strain was recently discovered in South Africa and has spread to 29 countries

Preliminary data and analysis obtained from the local area indicate that the epidemic in South Africa will increase exponentially, and Omicron seems to be able to reinfect survivors infected with other strains of the new coronavirus

On December 2, 2021, researchers from Harvard University Medical School in the United States published a research paper titled "Structural Basis for Continuous Antibody Escape of SARS-CoV-2 Receptor Binding Domain" in the top international academic journal "Science"

The study predicted the future evolution strategy of SARS-CoV-2 and discovered several possible mutations that allow the virus to evade immune defenses, including natural immunity obtained through infection or vaccination, and antibody-based treatments

When this study was published, a new variant called Omicron received widespread attention, and it was later discovered that Omicron contained several antibody escape mutations that the researchers predicted in the study

The researchers said that these findings are not directly applicable to Omega, because this particular mutation will depend on the interaction between its own unique set of mutations (at least 30)

The results of this study indicate that special attention should be paid to Omicron mutations, as these mutations have been shown to avoid antibodies used to treat newly infected patients and antibodies from mRNA vaccines

In this study, in order to estimate how the virus might transform itself in the next step, the researchers tracked clues to the chemical and physical structure of the virus, and looked for rare mutations in immunodeficiency individuals and global virus sequence databases

Researchers focused on the spike protein of the coronavirus, called the receptor binding domain, which the virus uses to bind to human cells

The working principle of most antibodies is to lock the same position in the receptor binding region of the viral spike protein to prevent it from binding to cells and causing infection

In order to prove that viruses can produce a large number of escape mutations, the researchers constructed a virus model, which is a combination of harmless non-infectious virus-like particles and SARS-CoV-2 spike protein fragments containing suspected escape mutations

Escape the therapeutic antibody and mRNA vaccine serum

Studies have found that models containing up to 7 of these escape mutations can resist the neutralization of therapeutic antibodies and serum from mRNA vaccine recipients
.

With the advent of Omicron variants, the researchers say that the level of complex mutations in the receptor-binding region is no longer a hypothesis
.
The delta mutant has only two mutations in its receptor binding region, up to 7 mutations, but Omicron has 15, including several specific mutations analyzed by the researchers
.

In a series of experiments, the researchers conducted biochemical analysis and model tests to understand how antibodies bind to spike proteins that contain escape mutations
.
Some of these mutations, including those found in Omega, allow the model to avoid therapeutic antibodies altogether
.

In addition, the researchers also discovered an antibody that can effectively neutralize all test variants
.
However, if a single mutation occurs in the spike protein and a sugar molecule is added where the antibody binds to the virus, the virus will be able to avoid the antibody
.

Add sugar molecules where the antibody binds to the virus to drive neutralization and escape

Researchers’ previous results on variants with fewer mutations have shown that these new, highly mutated variants can also cleverly evade antibodies acquired through natural infections
.

In another experiment, these models were exposed to the serum of individuals receiving mRNA vaccines
.
For some highly mutated mutations, the serum of single-dose vaccine recipients completely loses the ability to neutralize the virus
.
In samples collected from people who received the second dose of the vaccine, they maintained a certain degree of effectiveness against all variants, including some pseudotypes with widespread mutations
.

In view of the great structural flexibility of the SARS-CoV-2 spike protein in this study, Omega is unlikely to be the end of this virus
.
Therefore, it is necessary to continue to pay attention and be alert to the emergence of new mutant strains
.

Article link: https:// strains are evolving new ways to evade antibodies and vaccines
.