Transition of Antibody Titers after SARS-CoV-2 mRNA Vaccination in Japanese Healthcare Workers

Abstract

Since February 2021, healthcare workers in Japan have been preferentially vaccinated with a messenger RNA vaccine (BNT162b2/Pfizer) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While many studies have confirmed that this vaccine is highly effective in reducing hospitalizations and deaths from coronavirus disease 2019 (COVID-19), antibody titers tend to decline at 3 months, leading to a risk of breakthrough infections. Thus, information is needed to support decision making regarding the third vaccination. In this study, we investigated transition of the anti-SARS-CoV-2 spike protein receptor-binding domain (RBD) IgG and neutralizing antibody titers of 37 vaccinated Japanese healthcare workers. Samples were collected six times starting

B cell receptor repertoire analysis from autopsy samples of COVID-19 patients

“…An improved technique is needed to obtain high-quality RNA in adequate quantities from FFPE samples, as not all BCRs can be isolated effectively owing to the limited sample volume and sequencing depth. Although the SARS-CoV-2 neutralizing activity of artificial antibodies synthesized from lung FFPE tissue was superior to vaccine-naïve plasma IgG and similar to 2 nd vaccinetreated groups, the SARS-CoV-2 neutralizing effect of the plasma specimens in peripheral blood enhances with the number of mRNA vaccine intakes and the timing of the analysis after vaccination (24). Enriched IgG from peripheral blood may contain a high proportion of antibodies to SARS-CoV-2 due to vaccine injection, but also antibodies to a variety of other antigens.…”

“…A second assay was performed to evaluate the neutralizing antibody using the plaque reduction neutralizing test (PRNT) with live viruses (20,24). The SARS-CoV-2 S protein (319-541 aa) monoclonal antibody for neutralization (0.1-100 mg; Catalog #67758-1, Proteintech, IL, U.S.A.) was incubated with equal volumes of 100 plaque-forming units of SARS-CoV-2 (nCoV-19/ JPN/TY/WK521/2020, National Institute of Infectious Disease, Japan) at 37°C for 1 h. Half of the virus-serum mixture was then infected with VeroE6/TMPRSS2 cells (JCRB1819, JCRB Cell Bank, Japan) at 37°C for 1 h and covered with agarose overlay.…”