The 50% plaque reduction neutralization assay (PRNT) has been previously used to assess the neutralization capacity of donor plasma against wild-type and variant of concern (VOC) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging data suggest that plasma with an anti-SARS-CoV-2 level of ≥2 × 10 binding antibody units/mL (BAU/mL) protects against SARS-CoV-2 Omicron BA.1 infection.
View Article and Find Full Text PDFThere is evidence that COVID-19 convalescent plasma may improve outcomes of patients with impaired immune systems; however, more clinical trials are required. Although we have previously used a 50% plaque reduction/neutralization titer (PRNT) assay to qualify convalescent plasma for clinical trials and virus-like particle (VLP) assays to validate PRNT methodologies, these approaches are time-consuming and expensive. Here, we characterized the ability of the Abbott severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2 characterized by both VLP assays and PRNT.
View Article and Find Full Text PDFOur group has previously used laboratory and commercially developed assays to understand the IgG responses to SARS-CoV-2 antigens, including nucleocapsid (N), spike (S), and receptor binding domain (RBD), in Canadian blood donors. In this current study, we analyzed 17,428 available and previously characterized retention samples collected from April 2020 to March 2021. The analysis compared the characteristics of the Abbott SARS-CoV-2 IgG II Quant assay (Abbott anti-spike [S], Abbott, Chicago, IL) against four other IgG assays.
View Article and Find Full Text PDFObjective: CD4+CD8+ double-positive T-cells (DPTs) have been classified as a separate T-cell subpopulation, with two main phenotypes: CD4 CD8 and CD4 CD8. In recent years, the relevance of DPTs in the pathogenesis of infections, tumors, and autoimmune diseases has been recognized. Reference values among healthy individuals remain unknown.
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