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EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-323146


The breadth of the humoral immune response following SARS-CoV-2 infection was indicated to be important for recovery from COVID-19. Recent studies have provided valuable insights regarding the dynamics of the antibody response in symptomatic COVID-19 patients. However, the information regarding the dynamics of the serological and cellular memory in COVID-19 recovered patients is scarce. It is imperative to determine the persistence of humoral memory in COVID-19 recovered patients as it will help to evaluate the susceptibility of recovered patients to re-infection. Here, we describe the dynamics of both the SARS-CoV-2 specific serological and B cell response in COVID-19 recovered patients. We found that acute phase SARS-CoV-2 patients mount a rapid, robust antibody response following infection however, the serological memory decays in COVID-19 recovered patients over the period of six months. Using an in vitro neutralization assay revealed a strong correlation between total RBD-specific (RBD+) antibodies and neutralizing antibodies suggesting that antibody levels can be used as proxy to determine neutralizing capacity. In contrast to the antibody decay observed in recovered patients, the RBD+ memory B cell (mBC) frequency was found to be stable over time. Moreover, the frequency of RBD+ B cell plasmablasts (PB) was found to be associated with the RBD+ IgG levels. B cell receptor sequencing (BCR-Seq) of RBD+ PB show unregular high frequency of the IgG4 isotype which is known to contribute to the manifestation of IgG4 related disease and other autoimmune diseases. These data, suggests that the differentiation of short-lived PB to become long-lived plasma cells may be impaired and the main contributor of antibody production in recovered COVID-19 patient are the short-lived PB that predominantly encode to IgG4 subclass. The skewed class switch towards IgG4 may contribute to the severeness of the COVID-19 morbidity. Moreover, the persistence of RBD+ mBC following recovery may contribute to a robust recall humoral response in a case of re-infection by SARS-CoV-2. Overall, our data obtained in this study reveals a discordance between serological and cellular memory in COVID-19 recovered patients which has important implications on re-infection susceptibility and vaccine design.Ethical Approval: All patients provided informed consent to the use of their data and clinical samples for the purposes of the present study and blood collection was performed under institutional review board approvals number 0001281-4 and 0000406-1. All blood samples were collected at the Hasharon Hospital, Rabin Medical Center under ethical approval number 0265-20.

Nat Commun ; 12(1): 6222, 2021 10 28.
Article in English | MEDLINE | ID: covidwho-1493103


The importance of breastmilk in postnatal life lies in the strong association between breastfeeding and the reduction in the risk of infection and infection-related infant mortality. However, data regarding the induction and dynamics of breastmilk antibodies following administration of the Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine is scarce, as pregnant and lactating women were not included in the initial vaccine clinical trials. Here, we investigate the dynamics of the vaccine-specific antibody response in breastmilk and serum in a prospective cohort of ten lactating women who received two doses of the mRNA vaccine. We show that the antibody response is rapid and highly synchronized between breastmilk and serum, reaching stabilization 14 days after the second dose. The response in breastmilk includes both IgG and IgA with neutralization capacity.

Breast Feeding , COVID-19 Vaccines/genetics , RNA, Messenger/blood , Adult , Animals , Antibody Formation/genetics , Antibody Formation/physiology , Female , Humans , Milk/chemistry , RNA, Messenger/analysis , Vaccines, Synthetic/therapeutic use