Humoral immunity in dually vaccinated SARS-CoV-2-naïve individuals and in booster-vaccinated COVID-19-convalescent subjects.

BACKGROUND: The immune response to COVID-19-vaccination differs between naïve vaccinees and those who were previously infected with SARS-CoV-2. Longitudinal quantitative and qualitative serological differences in these two distinct immunological subgroups in response to vaccination are currently not well studied. METHODS: We investigate a cohort of SARS-CoV-2-naïve and COVID-19-convalescent individuals immediately after vaccination and 6 months later. We use different enzyme-linked immunosorbent assay (ELISA) variants and a surrogate virus neutralization test (sVNT) to measure IgG serum titers, IgA serum reactivity, IgG serum avidity and neutralization capacity by ACE2 receptor competition. RESULTS: Anti-receptor-binding domain (RBD) antibody titers decline over time in dually vaccinated COVID-19 naïves whereas titers in single dose vaccinated COVID-19 convalescents are higher and more durable. Similarly, antibody avidity is considerably higher among boosted COVID-19 convalescent subjects as compared to dually vaccinated COVID-19-naïve subjects. Furthermore, sera from boosted convalescents inhibited the binding of spike-protein to ACE2 more efficiently than sera from dually vaccinated COVID-19-naïve subjects. CONCLUSIONS: Long-term humoral immunity differs substantially between dually vaccinated SARS-CoV-2-naïve and COVID-19-convalescent individuals. Booster vaccination after COVID-19 induces a more durable humoral immune response in terms of magnitude and quality as compared to two-dose vaccination in a SARS-CoV-2-naïve background.

An Overview of Mouse Models of Nonalcoholic Steatohepatitis: From Past to Present.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the Western world. It is associated with obesity and type 2 diabetes and represents a spectrum of histological abnormalities ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), which can further progress to fibrosis, cirrhosis, hepatocellular carcinoma (HCC), and liver failure. To gain insight into the pathogenesis and evaluate treatment options, mouse models of NAFLD/NASH are of utmost importance. There is a high phenotypical variety in the available mouse models, however, models that truly display the full spectrum of histopathological and metabolic features associated with human NASH are rare. In this review, we summarize the most important NAFLD/NASH mouse models that have been developed over the years and briefly highlight the pros and cons. Also, we illustrate the preclinical research in which these models have been used. © 2016 by John Wiley & Sons, Inc.