ABSTRACT
The onset of severe SARS-CoV-2 infection is characterized by the presence of afucosylated IgG1 responses against the viral spike (S) protein, which can trigger exacerbated inflammatory responses. Here, we studied IgG glycosylation after BNT162b2 SARS-CoV-2 mRNA vaccination to explore whether vaccine-induced S protein expression on host cells also generates afucosylated IgG1 responses. SARS-CoV-2 naive individuals initially showed a transient afucosylated anti-S IgG1 response after the first dose, albeit to a lower extent than severely ill COVID-19 patients. In contrast, previously infected, antigen-experienced individuals had low afucosylation levels, which slightly increased after immunization. Afucosylation levels after the first dose correlated with low fucosyltransferase 8 (FUT8) expression levels in a defined plasma cell subset. Remarkably, IgG afucosylation levels after primary vaccination correlated significantly with IgG levels after the second dose. Further studies are needed to assess efficacy, inflammatory potential, and protective capacity of afucosylated IgG responses. One sentence summaryA transient afucosylated IgG response to the BNT162b2 mRNA vaccine was observed in naive but not in antigen-experienced individuals, which predicted antibody titers upon the second dose.
ABSTRACT
To treat the SARS-CoV-2 virus, that enters the body through the respiratory tract, different vaccines in particular against the SARS-CoV-2 spike (S)-protein have been developed or are in the development process. For the BioNTech / Pfizer mRNA vaccine BNT162b2, which is injected twice, protection against COVID-19 has been described for the first weeks after the second vaccination. The underlying mechanisms of defense and the long-term effectiveness of this vaccine against COVID-19 are currently under investigation. In addition to the induction of systemic antibodies (Abs), Ab responses in the respiratory tract would help to form a first line of defense against SARS-CoV-2. Furthermore, protection depends on Fab-part-dependent neutralizing capacities, however, Fc-part-mediated effector mechanisms might also be important. Long-term defense would be based on the induction of long-lived antibody-producing plasma cells (PCs) and memory B cells. Here, we established different assays to analyze anti-SARS-CoV-2-S IgG and IgA Abs in blood serum and saliva as well as SARS-CoV-2-S1-reactive IgG and IgA PCs and potential memory B cells in the blood of individuals upon their first immunization with BNT162b2. We show that the vaccine induces in particular anti-SARS-CoV-2-S IgG1 and IgG3 as well as IgA1 and in some individuals also IgG2 and IgA2 serum Abs. In the saliva, we found no anti-SARS-CoV-2-S IgA, but instead IgG Abs. Furthermore, we found SARS-CoV-2-S reactive IgG+ blood PCs and potential memory B cells as well as SARS-CoV-2-S reactive IgA+ PCs and/or potential memory B cells in some individuals. Our data suggest that the vaccine induces a promising CD4+ T cell-dependent systemic IgG1 and IgG3 Ab response with IgG+ PCs and potential memory B cells. In addition to the systemic IgG response, the systemic IgA and saliva IgG response might help to improve a first line of defense in the respiratory tract against SARS-CoV-2 and its mutants.
ABSTRACT
Coronavirus disease 2019 (COVID-19) is a viral infection affecting multiple organ systems of great significance for metabolic processes. Thus. there is increasing interest in metabolic and lipoprotein signatures of the disease and early analyses have demonstrated metabolic pattern typical for atherosclerotic and hepatic damage in COVID-19 patients. However, it remains unclear whether these are specific for COVID-19 or a general marker of critical illness. To answer this question, we have analyzed 276 serum samples from 92 individuals using NMR metabolomics, including longitudinally collected samples from 5 COVID-19 and 11 cardiogenic shock intensive care patients, 18 SARS-CoV-2 antibody-positive individuals, and 58 healthy controls. COVID-19 patients showed a distinct metabolic serum profile, including changes typical for severe dyslipidemia and a deeply altered metabolic status compared to healthy controls. Specifically, VLDL parameters, IDL particles, large-sized LDL particles, and the ApoB100/ApoA1 ratio were significantly increased, whereas HDL fractions were decreased. Moreover, a similarly perturbed profile was apparent, even when compared to other ICU patients suffering from cardiogenic shock, highlighting the impact of COVID-19 especially on lipid metabolism and energy status. COVID-19 patients were separated with an AUROC of 1.0 when compared to both healthy controls and cardiogenic shock patients. Anti-SARS-CoV-2 antibody-positive individuals without acute COVID-19 did not show a significantly perturbed metabolic profile compared to age- and sex-matched healthy controls, but SARS-CoV-2 antibody-titers correlated significantly with metabolic parameters, including levels of glycine, ApoA2, and small-sized LDL and HDL subfractions. Our data suggest that NMR metabolic profiles are suitable for COVID-19 patient stratification and post-treatment monitoring.
