Journal: Scientific Reports

Article Title: Immune response and protective efficacy of the SARS-CoV-2 recombinant spike protein vaccine S-268019-b in mice

doi: 10.1038/s41598-022-25418-5

Figure Lengend Snippet: Induction of long-term immunity in mice administered S-910823 plus A-910823. ( a ) Study schedule schematic. On Day 0 and Day 14, female mice were intramuscularly administered 1 μg of S-910823 with or without A-910823 (n = 5/group). Spleens and bone marrow were collected on Day 83. ( b ) Flow cytometric analysis of the percentage of receptor-binding domain (RBD)-specific B-cells among CD73 + CD19 + B-cells. Each circle represents the percentage of cells in an individual mouse. The bars represent mean values, while error bars indicate standard deviation. ( c ) Detection of vaccine-induced antibody-secreting cells (ASCs) in bone marrow. Bone marrow cells were cultured for 2.5 h in an enzyme-linked immunospot (ELISPOT) assay plate wells which had been coated with SARS-CoV-2 spike protein. Results indicate the number of antigen-specific ASCs among 10 6 bone marrow cells. ( d , e ) Percentage of cytokine-producing T cells in the spleen. Splenocytes were restimulated ex vivo with or without SARS-CoV-2 spike-protein-derived peptides for 16 h. Levels of IL-2, IFN-γ, TNF-α, IL-4, and IL-5 from CD44 + CD4 + T cells ( d ) and levels of IFN-γ from CD44 + CD8 + T cells ( e ) were evaluated using cell-surface and intracellular staining and examined using flow cytometry. The open bars indicate non-stimulated splenocytes [peptide ( −)], while the solid bars indicate splenocytes stimulated with SARS-CoV-2 spike protein peptides [peptide ( +)]. The gray bars represent mice administered vehicle or S-910823 without adjuvant A-910823, while the rose bars represent mice administered S-910823 with A-910823. The open and solid circles represent the results of individual mice. The error bars indicate the standard deviation.

Article Snippet: The spots were counted using an immunospot S6 UNIVERSAL-V ELISPOT reader (Cellular Technology Limited, Beachwood, OH, USA).

Techniques: Binding Assay, Standard Deviation, Cell Culture, Enzyme-linked Immunospot, Ex Vivo, Derivative Assay, Staining, Flow Cytometry, Adjuvant