WHO International Standard for anti-SARS-CoV-2 immunoglobulin

Abstract

The development timeline of COVID-19 vaccines is unprecedented, with more than 300 vaccine developers active worldwide. 1 Vaccine candidates developed with various technology platforms targeting different epitopes of SARS-CoV-2 are in the pipeline. Vaccine developers are using a range of immunoassays with different readouts to measure immune responses after vaccination, making comparisons of the immunogenicity of different COVID-19 vaccine candidates challenging. In April, 2020, in a joint effort, the Coalition for Epidemic Preparedness Innovations (CEPI), the National Institute for Biological Standards and Control (NIBSC), and WHO provided vaccine developers and the entire scientific community with a research reagent for an anti-SARS-CoV-2 antibody. The availability of this material was crucial for facilitating the development of diagnostics, vaccines, and therapeutic preparations. This effort was an initial response when NIBSC, in its capacity as a WHO collaborating centre, was working on the preparation of the WHO International Standards. This work included a collaborative study that was launched in July, 2020, to test serum samples and plasma samples sourced from convalescent patients with the aim of selecting the most suitable candidate material for the WHO International Standards for anti-SARS-CoV-2 immunoglobulin. The study involved 44 laboratories from 15 countries and the use of live and pseudotype-based neutralisation assays, ELISA, rapid tests, and other methods. The outcomes of the study were submitted to WHO in November, 2020. The inter-laboratory variation was reduced more than 50 times for neutralisation and

Receptor-binding domain recombinant protein on alum-CpG induces broad protection against SARS-CoV-2 variants of concern

“…Sera from mice vaccinated with the CpG adjuvanted vaccine candidate maintained the ability to neutralize pseudoviruses which include key mutations, mimicking important variants of interest and concern. Human convalescent plasma (WHO International Standard for anti-SARS-CoV-2 immunoglobulin, NIBSC code: 20/136 [27]) showed reduced neutralization ability against the variant pseudoviruses, while the RBD219-N1C1/alum+CpG vaccine groups showed a reduction to a much lesser extent. Comparing the average IC50 values for the Wuhan pseudovirus, the 7 µg RBD219-N1C1/alum+CpG vaccine showed 5.5 times higher values, while the IC50 values for the B.1.351 pseudovirus (K417N, E484K, N501Y, D614G) are up to 20-fold higher ( Figure 3A ).…”

Review of Early Immune Response to SARS-CoV-2 Vaccination Among Patients With CKD

“…Therefore, we have chosen to provide only the proportion of individuals who developed detectable anti-SARS-CoV-2 antibodies (herein called “seropositivity”). Whilst the World Health Organisation’s initiative to establish a reference sample will go some way to allowing cross-platform comparisons (it has no impact on dynamic ranges), we must not conflate antibody levels reported in these early studies with precise clinical effectiveness [ 12 ] .…”

Preliminary evidence of blunted humoral response to SARS-CoV-2 mRNA vaccine in multiple sclerosis patients treated with ocrelizumab

“…Sera were stored at − 20 °C and tested using the LIAISON® SARS-CoV-2 TrimericS IgG assay (DiaSorin S.p.A., Saluggia, Italy), an indirect chemiluminescence immunoassay (CLIA) technology for the detection of serum IgG antibodies to SARS-CoV-2 trimeric spike protein (anti-TSP IgG), including neutralizing antibodies [ 6 ]. Performance and interpretation of results were done in accordance with the manufacturer’s instructions, and the IgG titers were expressed in Binding Antibody Units (BAU), an international standard unit, with 33.8 BAU/mL as cut-off value [ 7 ].…”