'Difference between immunity due to infection with new corona and immunity due to vaccine' was found, which immunity is stronger?
While there is a preprinted paper saying that '
Antibodies elicited by mRNA-1273 vaccination bind more broadly to the receptor binding domain than do those from SARS-CoV-2 infection
https://www.science.org/doi/10.1126/scitranslmed.abi9915
How Immunity Generated from COVID-19 Vaccines Differs from an Infection – NIH Director's Blog
https://directorsblog.nih.gov/2021/06/22/how-immunity-generated-from-covid-19-vaccines-differs-from-an-infection/
With the emergence of 'variant of concern ' represented by the delta strain of the new coronavirus, it is feared that the immunity obtained from past infections and vaccinations will be difficult to work. Therefore, the research team of Jesse Bloom and Allison Greaney of Fred Hutchinson Cancer Research Center in Seattle, USA, said that the part called 'receptor binding site (RBD)' in the spike protein protruding from the surface of the new coronavirus. I conducted a study focusing on.
RBD is a site that binds receptors on the surface of human cells to viral spike proteins. If RBD does not work, the virus cannot penetrate into human cells well, so whether or not RBD can be recognized is an important point for both 'immunity obtained from past infections' and 'immunity obtained from vaccines'. That thing.
However, since many mutations can occur in RBD, even if the human immune system can recognize a specific RBD, it may not be possible to deal with the emergence of mutant strains of viruses with RBDs with different structures. There is a sex.
Therefore, the research team created a library that covers about 3800 mutations that can occur in RBD. 'Deep mutation' that examines in parallel how antibodies collected from people who have been vaccinated twice with Moderna's mRNA and those who have been infected with the new coronavirus in the past react to these RBDs. We used a technique called the 'scan method' to investigate whether the immune system could respond appropriately to mutations in RBD.
As a result of the investigation, it was found that the antibody induced by the vaccine focused on RBD, whereas the antibody induced by the past infection often targeted the part other than RBD in the peplomer. Did. We also found that vaccine immunity was more likely to target specific parts of RBD, whereas vaccine immunity was evenly targeted at different locations in RBD.
Regarding the results of this study, Francis Collins, director of the National Institutes of Health, said, 'It was suggested that the difference in the method of identifying antibodies is the difference between immunity due to infection and immunity due to vaccine. The resulting antibody has the potential to respond strongly to the emergence of new variants of the new coronavirus, and more importantly, experience of recovery after infection with the new coronavirus. It has also been shown that even humans can expect further protective effects by receiving the vaccine. '
It is not clear why there is such a difference between vaccine-induced and infectious antibodies. The researchers speculate that the vaccine presents the viral protein in a slightly different form, which may in turn lead to the flexibility of the immune response to accommodate different RBD shapes.
He also said that ' it is important that mRNA is involved' and that 'normal infections expose only the respiratory tract to the virus unless it is very severe, whereas the vaccine is administered directly to the muscles, so immunity is immunized. There is also a theory that it reacts more greatly.
'In any case, the new coronavirus causes a variety of mutations similar to the normal human coronavirus, which is the causative virus of the common cold, while the vaccine is suggested to remain effective against those mutations,' said Collins. Therefore, the greatest hope to win the fight against the pandemic is to get as many people as possible vaccinated, whether or not they have been infected with the new coronavirus. Not only will it be saved, but it will also reduce the likelihood of the emergence of mutant strains that existing vaccines cannot handle. '
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