Objective: Standardised quantitative analysis of the humoral immune response to SARS-CoV-2 antigens may be useful for estimating the extent and duration of immunity. The aim was to develop enzyme-linked immunosorbent assays (ELISAs) for the quantification of human IgG antibodies against SARS-CoV-2 antigens.
Methods: Enzyme-linked immunosorbent assays were developed based on monoclonal antibodies against human IgG and recombinant SARS-CoV-2 antigens (Spike-S1 and Nucleocapsid). The WHO 67/086 immunoglobulin and WHO 20/136 SARS-CoV-2 references were used for standardisation. Sera of a study group of COVID-19-positive subjects ( = 144), pre-pandemic controls ( = 135) and individuals vaccinated with BioNTech-Pfizer BNT162b2 vaccine ( = 48) were analysed. The study group sera were also tested using EuroImmun SARS-CoV-2-ELISAs and a quantitative S1-specific fluorescence enzyme immunoassay (FEIA) from Thermo Fisher.
Results: The ELISA results were repeatable and traceable to international units because of their parallelism to both WHO references. In the study group, median anti-S1-IgG concentrations were 102 BAU mL, compared to 100 and 1457 BAU mL in the vaccination group after first and second vaccination, respectively. The ELISAs achieved an area under the curve (AUC) of 0.965 (S1) and 0.955 (Nucleocapsid) in receiver operating characteristic (ROC) analysis, and a specificity of 1 (S1) and 0.963 (Nucleocapsid) and sensitivity of 0.903 (S1) and 0.833 (Nucleocapsid) at the maximum Youden index. In comparison, the commercial assays (S1-FEIA, S1 and Nucleocapsid ELISA EuroImmun) achieved sensitivities of 0.764, 0.875 and 0.882 in the study group, respectively.
Conclusions: The quantitative ELISAs to measure IgG binding to SARS-CoV-2 antigens have good analytical and clinical performance characteristics and units traceable to international standards.
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http://dx.doi.org/10.1002/cti2.1369 | DOI Listing |
Front Immunol
January 2025
RNAimmune, Inc., Germantown, MD, United States.
Background: The unrelenting emergence of SARS-CoV-2 variants has significantly challenged the efficacy of existing COVID-19 vaccines. Enhancing the stability and immunogenicity of the spike protein is critical for improving vaccine performance and addressing variant-driven immune evasion.
Methods: We developed an mRNA-based vaccine, RV-1730, encoding the Delta variant spike protein with the S6P mutation to enhance stability and immunogenicity.
Elucidating the relationships between a class I peptide antigen, a CD8 T cell receptor (TCR) specific to that antigen, and the T cell phenotype that emerges following antigen stimulation, remains a mostly unsolved problem, largely due to the lack of large data sets that can be mined to resolve such relationships. Here, we describe Antigen-TCR Pairing and Multiomic Analysis of T-cells (APMAT), an integrated experimental-computational framework designed for the high-throughput capture and analysis of CD8 T cells, with paired antigen, TCR sequence, and single-cell transcriptome. Starting with 951 putative antigens representing a comprehensive survey of the SARS-CoV-2 viral proteome, we utilize APMAT for the capture and single cell analysis of CD8 T cells from 62 HLA A*02:01 COVID-19 participants.
View Article and Find Full Text PDFThe long-term effects of repeated COVID-19 vaccinations on adaptive immunity remain incompletely understood. Here, we conducted a comprehensive three-year longitudinal study examining T cell and antibody responses in 78 vaccinated individuals without reported symptomatic infections. We observed distinct dynamics in Spike-specific humoral and cellular immune responses across multiple vaccine doses.
View Article and Find Full Text PDFHum Vaccin Immunother
December 2025
Department of Infectious Disease, Imperial College London, London, UK.
The COVID-19 pandemic highlighted the need for rapidly deployable, flexible vaccine platforms; particularly RNA which is now being explored for several other pathogens. DNA vaccines have potential advantages over RNA, including cost of manufacture, ease of storage and potentially lower reactogenicity. However, they have historically underperformed in large animals and human trials due to low immunogenicity.
View Article and Find Full Text PDFRespir Res
January 2025
Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, 14080, Mexico.
Background: Post-COVID-19 respiratory sequelae often involve lung damage, which is called residual lung abnormalities, and potentially lead to chronic respiratory issues. The adaptive immune response, involving T-cells and B-cells, plays a critical role in pathogen control, inflammation, and tissue repair. However, the link between immune dysregulation and the development of residual lung abnormalities remains unclear.
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