According to foreign media reports, the worrying variant of the new coronavirus can avoid neutralizing antibodies to the original virus.A new study from Washington University School of medicine in St. Louis shows that three new, rapidly spreading variants of the virus that cause cowid-19 can avoid antibodies against the original form of the virus that triggered the pandemic.With a few exceptions, the researchers found that more antibodies were needed to neutralize the new mutation, whether they were produced for vaccination or natural infection, or purified for drug use.
It is reported that the results of this laboratory based experiment were published in nature medicine on March 4, 2021. The research results show that with the new variety dominating, the drugs and vaccines developed so far may become less effective. Experts say that this is inevitable. The researchers studied South African, British and Brazilian variants.
Professor Michael S. diamond, senior author of the study, said: "we are worried that people who have been infected with or vaccinated with cowid-19 would have antibody protection levels, but they may not be able to resist the new variants. A person's antibodies to vaccines or natural infections vary widely. Some people have very high antibody levels, but they may still be immune to this worrying new variant. But some people - especially the elderly and immunocompromised people - may not produce such high levels of antibodies. If the antibody levels needed for protection increase tenfold, as our data show, they may not be enough. The worry is that those who need protection most are least likely to be protected. "
Sars-cov-2, the virus that causes covid-19, uses a protein called spike to approach and enter the cell. People infected with sars-cov-2 produce the most antibodies against spike proteins.
Therefore, spike protein has become the main target of drug and vaccine developers of covid-19. Three kinds of vaccines approved by the US Food and Drug Administration (FDA) for emergency use -- Pfizer / biontech, Moderna and Johnson & Johnson -- all aimed at the peak and selected effective anti spike antibodies to develop anti-covid-19 antibody drugs.
The virus is always mutating, but in the past year, the mutations in sars-cov-2 have not threatened this spike protein based strategy. Then, this winter, rapidly spreading variants were found in the UK, South Africa, Brazil and elsewhere. Worryingly, these new variants carry multiple mutations in their spike genes, which may reduce the effectiveness of current spike targeted drugs and vaccines for the prevention or treatment of covid-19. The most worrying new varieties are b.1.1.7 (UK), b.1.135 (South Africa) and b.1.1.248 (Brazil).
To assess whether the new variants could evade antibodies against the original form of the virus, diamond and his colleagues, including first author Rita E. Chen, a graduate student at Diamond's laboratory, tested the neutralization ability of the antibodies against the three virus variants in the laboratory.
The researchers tested the variation of antibodies in the blood of people who recovered from sars-cov-2 infection or had been vaccinated with Pfizer vaccine. They also tested antibodies in the blood of mice, hamsters and monkeys that had been vaccinated with an experimental covid-19 vaccine developed by the University of Washington School of medicine. The vaccine can be injected through the nose. B. 1.1.7 (UK) the variant can be neutralized with a similar level of antibody required to neutralize the original virus. But the other two variants require 3.5 to 10 fold antibodies to neutralize.
Then they tested monoclonal antibodies: mass-produced copies of individual antibodies that are particularly good at neutralizing the original virus. When the researchers tested a new strain of the virus with a set of monoclonal antibodies, the results ranged from broadly valid to completely invalid.
"We don't know exactly what the consequences of these new mutations will be," Diamond said. "Antibodies are not the only protection; other parts of the immune system may be able to compensate for increased antibody resistance. This will be determined over time, and from an epidemiological point of view, we can see what happens as these mutations spread. Will we see reinfection? Will we see vaccine failure and drug resistance? I hope not. But it is clear that we will need to constantly screen antibodies to ensure that they are still effective when new mutations emerge and spread, and may adjust our vaccine and antibody treatment strategies. "