Recent studies have shown that the B.1.351 variant can even resist the plasma of convalescent patients and the serum of vaccinated patients. Other work carried out under laboratory conditions reminds us that our defense system is complex and will not stand idly by when SARS-CoV-2 is mutated.
In recent months, there have been three “Worrying variant” (English, Changes to watch, SARS-CoV-2. One of the reasons behind the name is that our immune response (whether natural immunity or immune response mediated by vaccines and treatments against covid-19) may be weakened by this.an article Published in the magazine this week natural The results of laboratory experiments provide us with some enlightenment.
Several researchers from Columbia University in the United States analyzed the susceptibility of mutant viruses to real and artificial viruses (pseudoviruses) B.1.1.7 (UK) with B.1.351 (South Africa) Neutralize with 30 Monoclonal antibodies, plasma 20 recovering patients and serum 22 vaccinated people.
Regeneron, a biotechnology company responsible for one of the monoclonal antibody treatments, participated in this work. Its effectiveness jeopardizes these variants. This is because these therapies are designed to combat different versions of SARS-CoV-2 by binding to specific areas of the virus that has changed too much today.
The results show that the dominant B.1.1.7 variants in countries such as the United Kingdom and Israel can resist the neutralization of most monoclonal antibodies, which target one of the peak regions (N domains) affected by mutations . , NTD). However, it cannot be cleared from the plasma of patients who have overcome the disease, nor can it escape from the serum of people who have been vaccinated against covid-19.
These differences are due to the fact that monoclonal antibodies are the same and can bind to the same site, so mutations can prevent their task. On the contrary, in our body, the immune response is more complicated, including a mixture of multiple different antibodies, and other measures, which make it difficult to cause problems under actual conditions.Data from countries such as Israel and the United Kingdom, and Published in magazines like this NEJM, Confirming the view that a vaccine against covid-19 can work against variant B. 1.1.7.
The problem with the South African variant
The author believes that experiments using the B.1.351 variant, which is now dominant in South Africa, is one of the most frightening in terms of immune response and vaccines.
In this case, they not only observed the resistance of monoclonal antibodies against NTD domain, but also resistance against RBD (receptor binding domain). This is the area affected by the most characteristic mutation E484K of this variant.
The researchers also observed that the resistance of patients during the recovery period and vaccinated patients was about 10 times higher than that of plasma. The study author wrote: “B.1.351 and other variants with similar mutations in the burst present new challenges to monoclonal antibody therapy and threaten the protective efficacy of current vaccines.”
These results are consistent with other recent results.a job Posted last week on Natural medicine It is warned that the South African variant pseudovirus has shown “essentially escaped completely” under laboratory conditions to restore the plasma levels in patients with con healing.
The researchers did not use the P.1 (Brazil) variant in the study, but because it shares certain mutations with B.1.351, they believe it may show similar resistance. despite this, Pending review before publication The results shared this month are contrary to the hypothesis: The variant was found to be resistant to multiple monoclonal antibodies, but resistant to the plasma of convalescent patients, especially those of vaccinated people.
For this reason, the author of the pre-publication concluded: “P.1 variants threaten current antibody therapy, but the protective efficacy of our vaccines has been weakened.” About this work, from Icahn Mount Sinai (USA) The immunologist at the medical school assured people that this variant in Brazil “It seems to be a small problem” South Africa
Real life is different from the laboratory
It is important to note that the results of experiments performed under laboratory conditions (sometimes using artificial viruses) do not have to accurately reflect what happens when the virus infects a real human body. E.g, Reuters Guaranteed Oxford/AstraZeneca (AstraZeneca) is about to release data showing that their vaccine is effective against the Brazilian variant.In addition, research Posted this week NEJM Shows that Pfizer’s vaccine can neutralize all three variants of interest.
Even laboratory experiments remind us that the immune system is complex, and most importantly, it does not stare when the virus adapts.Peer review before publication Share this week It shows that antibodies have also evolved to gain “resilience” against mutations of their enemies. Otherwise, “will make SARS-CoV-2 get rid of its neutralizing effect.”
other Preprint, it is Shared last weekTo ensure that the immunization work involved in the terrible South African variant is not wasted. Their results concluded that the serum of patients who were previously infected with B.1.351 not only effectively neutralized it, but also killed the original variant, even the Brazilian variant.
“These data indicate that the antibody response of patients infected with the South African variant has a wide range of specificities, and the design of the vaccine [con la secuencia de la B.1.351] They can get cross answers,” the author wrote.
In addition, we must add that antibodies are not the only weapon possessed by the immune system: Recent publications Point out the variant pairs for the UK, South Africa, Brazil and California T lymphocytesThe cell specifically kills those companions who are infected by the coronavirus.