Pfizer-BioNTech and Moderna COVID-19 vaccines establish recall responses to reinfection
▻https://www.news-medical.net/news/20210718/Pfizer-BioNTech-and-Moderna-COVID-19-vaccines-establish-recall-respons
En faveur d’une mémoire de l’immunité anti sars-cov2
Également retrouvé partiellement après une infection, avec même une « supériorité » de cette dernière concernant les CD8,
While neutralizing antibody titers following the first vaccine dose were comparable to those among convalescent individuals, significantly higher levels were observed in the vaccinees following the booster dose.
However, several important B cell adaptations were shared between vaccinees and convalescent individuals .
Analysis by flow cytometry revealed a reduction in the level of naïve B cells, but an expansion of memory B cells in both groups.
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Importantly, the team observed a modest expansion of plasmablasts and a significant increase in spike-specific B cells just two weeks following a second vaccine dose, indicating the establishment of durable memory and potential recall responses to infection.
Single-cell analyses also revealed an expansion of activated CD4+ T cells and robust spike-specific polyfunctional CD4 T cell responses following vaccination.
Frequencies of activated CD8 T cells were comparable between the vaccinated and convalescent groups. However, natural infection induced the expansion of larger CD8 T cell clones, including distinct clusters.
This is likely due to the recognition of a broader set of epitopes presented by the virus that is not found in the mRNA vaccines, say the researchers.
source : ▻https://www.biorxiv.org/content/10.1101/2021.07.14.452381v1