Journal: Microbes and Infection

Article Title: Heterologous chimpanzee adenovirus vector immunizations for SARS-CoV-2 spike and nucleocapsid protect hamsters against COVID-19

doi: 10.1016/j.micinf.2022.105082

Figure Lengend Snippet: Viral loads and lung pathology. [A] Experimental design. [B,C] Viral RNA [B] and sgRNA [C] loads in oral swabs collected after challenge on days 2 and 4 for all animals and on days 7 and 14 for the day 14 euthanasia group animals. Significant difference between groups for each time point were calculated by two-Way repeated measures ANOVA with Tukey correction; they are indicated with lines and stars above as in legend to . [D,E] Lung viral RNA [D] and sgRNA [E] titers are shown for individual hamsters of the day 4 and day 14 euthanasia groups. Differences were calculated by two-Way ANOVA with Tukey correction, with lines and stars showing significant differences as in legend to . [F,G] SARS-CoV-2 TCID 50 titers in nares [F] and lungs [G] were determine on day 4 after challenge. Data were analyzed by an uncorrected Kruskal-Wallis test. [H] Sum of lung lesions for the day 4 and day 14 euthanasia group. Differences were calculated by two-Way ANOVA with Tukey correction, with lines and stars above as in legend to . [I] Severity of the different types of lesions according to gender of the animals.

Article Snippet: Sera were tested for inhibition of ACE binding to the RBD of the S protein by the Anti-SARS-CoV-2 Neutralizing Antibody Titer Serologic Assay Kit from Acro Biosystems (Newark, DE) following the manufacturer’s instructions.

Techniques:

Journal: medRxiv

Article Title: Anti-Spike IgG4 and Fc Effector Responses: The Impact of SARS-CoV-2 Vaccine Platform–Specific Priming and Immune Imprinting

doi: 10.1101/2025.03.19.25324267

Figure Lengend Snippet: Anti-Spike (rS) IgG isotypes in subjects primed with either with mRNA vaccines (mRNA-1273 or BNT162b2) or the protein-based subunit COVID-19 vaccine (NVX-CoV2373). Pre-booster (day 0), post-booster NVX-CoV2373 (day 28) or mRNA (BNT162b2) vaccines (day 29). A. Schematic of the vaccines administered to subjects. ELISA-based quantitation [Geometric Mean Titers (GMT) with 95% confidence intervals (CI)] of IgG isotypes is shown in B–E : Gray – mRNA vaccines x3 +NVX-CoV2373 (N=19), dark-blue – NVX-CoV273 x3 + NVX-CoV273 (N=18), F–I: Light-blue – NVX-CoV273 x2 + BNT162b2 (N=24 for Day 0 and N=30 for Day 29). Statistical analysis was performed by the two-tailed Mann–Whittney test. **p<0.01, ***p < 0.001, ****p < 0.0001.n.s. indicates not significant.

Article Snippet: An anti–SARS-CoV-2 S RBD IgG1/IgG2/IgG3/IgG4 monoclonal antibody (Acro Biosystems, Newark, DE, USA) were used as reference standards for each respective assay.

Techniques: Vaccines, Enzyme-linked Immunosorbent Assay, Quantitation Assay, Two Tailed Test

Journal: medRxiv

Article Title: Anti-Spike IgG4 and Fc Effector Responses: The Impact of SARS-CoV-2 Vaccine Platform–Specific Priming and Immune Imprinting

doi: 10.1101/2025.03.19.25324267

Figure Lengend Snippet: Anti-Spike (rS) IgG isotype proportions in subjects receiving the protein-based subunit XBB.1.5 COVID-19 vaccine (NVX-CoV2601) after priming with mRNA vaccines (≥3x). Pre-booster (day 0), post-booster with the NVX-CoV2601 vaccine (day 28). A. Anti-rS IgG isotype proportions (pie chart) against the wild-type (WT) trimer antigen (ancestral) B. Anti-rS IgG isotype proportions (pie chart) against the XBB.1.5 trimer antigen C. Anti-rS IgG isotype levels (GMT with 95% CI bar graph) against WT (Stripes, N=29) and XBB.1.5 (Solid color, N=29) trimer antigens. Geometric mean fold raise (GMFR) at day 28 post booster compared to pre-booster levels (day 0) are shown above the bars. Light-gray – anti-rS IgG1, medium-gray – anti-rS IgG2, black – anti-rS IgG3, plum – anti rS IgG4. Statistical analysis was performed by the two-tailed Mann–Whittney test. **p < 0.01, ***p<0.001 indicates significance. n.s. indicates not significant.

Article Snippet: An anti–SARS-CoV-2 S RBD IgG1/IgG2/IgG3/IgG4 monoclonal antibody (Acro Biosystems, Newark, DE, USA) were used as reference standards for each respective assay.

Techniques: Vaccines, Two Tailed Test

Journal: Vaccines

Article Title: Maternal Immunization with Adjuvanted Recombinant Receptor-Binding Domain Protein Provides Immune Protection against SARS-CoV-2 in Infant Monkeys

doi: 10.3390/vaccines12080929

Figure Lengend Snippet: Primary and secondary antibody responses of 5 adult female rhesus monkeys after immunization with adjuvanted recombinant spike protein-fusion protein (RBD-Fc) prior to conception. Mean (S.E.) antibody titers are shown in relative intensity units (RIUs) for the 1:10,000 serum dilution. Monkeys were screened at baseline to verify they had not been exposed previously to SARS-CoV-2. IgG levels increased significantly over time, crossing the threshold for seropositivity.

Article Snippet: To serve as Positive Controls, our assay protocol included anti-SARS-CoV-2 spike RBD neutralizing antibody (Human IgG1, ACRO Biosystems, SAD-S35, Lot # S35-211VF1-VT run at 1:100 and 1:1000, 1.0 µg/mL and 0.1 µg/mL, respectively), and a pooled human SARS-CoV-2 national IgG positive standard (Frederick National Laboratory Lot # COVID-NS0109, run at 1:10, 1:100 and 1:1000).

Techniques: Recombinant

Journal: Vaccines

Article Title: Maternal Immunization with Adjuvanted Recombinant Receptor-Binding Domain Protein Provides Immune Protection against SARS-CoV-2 in Infant Monkeys

doi: 10.3390/vaccines12080929

Figure Lengend Snippet: Mean (S.E.) spike protein-specific IgG levels in 6 mother and infant rhesus monkey pairs after delivery are shown in ( A ) (dark and light bars, respectively). Antibody titers were quantified at 3 serum dilutions (1:1000, 1:10,000, 1:100,000), and values are expressed in relative intensity units (RIUs). Maternal and neonatal antibody levels were similar at each dilution, resulting in a mean placental transfer rate of 100.3%. The ANOVA indicated only a significant effect of serum dilution ( F {2,15} = 133.1, p < 0.001). Individual data for all infants and the correlation with their mothers’ IgG titer at each dilution are shown in ( B ). Maternal and infant IgG levels were similar at each dilution, positively correlated at each dilution ( r = 0.77, p < 0.08; r = 0.74, p < 0.09, and r = 0.94, p < 0.01, respectively), and significantly correlated across the entire series ( r {18} = 0.98, p < 0.003). Regression lines are plotted to show the mother–infant association at each dilution. Placental transfer rate was calculated to be 100.3% and was markedly higher than the transfer rate of IgG transfer for tetanus IgG1, which was only 78%.

Article Snippet: To serve as Positive Controls, our assay protocol included anti-SARS-CoV-2 spike RBD neutralizing antibody (Human IgG1, ACRO Biosystems, SAD-S35, Lot # S35-211VF1-VT run at 1:100 and 1:1000, 1.0 µg/mL and 0.1 µg/mL, respectively), and a pooled human SARS-CoV-2 national IgG positive standard (Frederick National Laboratory Lot # COVID-NS0109, run at 1:10, 1:100 and 1:1000).

Techniques:

Journal: mAbs

Article Title: Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries

doi: 10.1080/19420862.2021.2002236

Figure Lengend Snippet: Identification of high-affinity mAbs against SARS-CoV-2 S1 subunit and pre-fusion stabilized S trimers. (a) Schematic of antibody library designs used in phage panning. Numbers on white text on green indicate the number of CDRs represented within each oligo pool per library. Purple blocks represent human or humanized germline framework regions; gray blocks represent llama framework regions. (b) Binding affinity of lead antibodies, as determined by SPR, demonstrating nanomolar binding to the SARS-CoV-2 spike S1 subunit. Leads from TB181 COVID-19 scFv and TB182 Fab libraries were reformatted and expressed as IgG1, while leads from TB201 VHH and TB202 VHH libraries were converted to VHH-Fc. Apparent binding affinity to spike trimers stabilized in the pre-fusion conformation are in the picomolar range. SPR experiments were performed on a Carterra LSA SPR biosensor, binding affinities were calculated by fitting to 1:1 model in Carterra Kinetics Tool software. See Materials and Methods for complete assay description. (c) Competition ELISA showing decreasing levels of S1 RBD binding to immobilized ACE2 on Nunc Maxisorp plates with increasing concentrations of antibody. The experiment was performed in singlicate. (d) inhibition flow cytometry experiment showing lowering levels of S1 RBD binding to Vero E6 cells expressing ACE2 as measured by decreasing mean fluorescence intensity (MFI) as antibody concentrations increase. The experiment was performed in triplicate with standard deviation shown as error bars

Article Snippet: We next investigated the cross-competition of the S1 antibody candidates and existing SARS-CoV-2 antibodies, including CR3022 and SAD-S35 (Acro Biosystems), with S1 using high-throughput SPR (HT-SPR).

Techniques: Binding Assay, Software, Enzyme-linked Immunosorbent Assay, Inhibition, Flow Cytometry, Expressing, Fluorescence, Standard Deviation

Journal: mAbs

Article Title: Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries

doi: 10.1080/19420862.2021.2002236

Figure Lengend Snippet: Sequence diversity and characterization of 235 SARS-CoV-2 S1-binding antibodies. Phylogenetic tree of SARS-CoV-2 S1-binding IgG (blue lines) and VHH-Fc (black lines) candidates identified by phage display. Green bars represent the binding affinity of each candidate as measured by SPR. Relative binding affinity is displayed linearly, a longer bar indicates improved binding affinity. The longest bar represents an observed binding affinity of 2 nM, the shortest visible bar represents 6.6 μM. No bar indicates no binding observed. Purple gradient represents the percent inhibition of each antibody in the Vero E6 competition assay at 100 nM mAb, weak inhibitors are represented in white, strong inhibitors are represented in purple. Phylogenetic tree data generated by aligning variable heavy sequences with MUltiple Sequence Comparison by Log-Expectation (MUSCLE). circular dendrogram figure constructed using interactive tree of life (iTOL).

Article Snippet: We next investigated the cross-competition of the S1 antibody candidates and existing SARS-CoV-2 antibodies, including CR3022 and SAD-S35 (Acro Biosystems), with S1 using high-throughput SPR (HT-SPR).

Techniques: Sequencing, Binding Assay, Inhibition, Competitive Binding Assay, Generated, Construct

Journal: mAbs

Article Title: Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries

doi: 10.1080/19420862.2021.2002236

Figure Lengend Snippet: Competition binning of SARS-CoV-2 S1-binding antibodies. Cross-competition of antibody candidates with SARS-CoV-2 S1 protein was assayed by high throughput (HT)-SPR using the carterra LSA. Red, yellow, and green cells in the heat map represent competitive, weakly competitive, and noncompetitive blocked analyte/ligand pairs, respectively. White cells represent unaddressed pairs in the assay. Numbers in cell indicate the relative binding response to SARS-CoV-2 S1 only

Article Snippet: We next investigated the cross-competition of the S1 antibody candidates and existing SARS-CoV-2 antibodies, including CR3022 and SAD-S35 (Acro Biosystems), with S1 using high-throughput SPR (HT-SPR).

Techniques: Binding Assay, High Throughput Screening Assay

Journal: mAbs

Article Title: Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries

doi: 10.1080/19420862.2021.2002236

Figure Lengend Snippet: Epitope mapping of SARS-CoV-2 S1-binding antibodies. (a) Solvent-accessible surface representation of spike protein trimer in closed (PDB: 6VXX) and open (PDB: 6VSB) conformations. VHH-Fc nanobodies (TB201, TB202) binding sites overlap with that of ACE2 in both conformations, while TB181 and TB182 IgGs access a more occluded region. (b) Cartoon representation of SARS-CoV-2 S protein RBD with critical residues highlighted as spheres for each monoclonal antibody. (c) Negative-staining electron microscopy analysis shows the distinct binding regions of antibodies identified from the distinct antibody libraries used in this study (colored surface). The SARS-CoV-2 spike protein NTD, C-terminal domain (CTD), RBD and bound ACE2 are shown as cartoon representations

Article Snippet: We next investigated the cross-competition of the S1 antibody candidates and existing SARS-CoV-2 antibodies, including CR3022 and SAD-S35 (Acro Biosystems), with S1 using high-throughput SPR (HT-SPR).

Techniques: Binding Assay, Negative Staining, Electron Microscopy