Journal: Diagnostics

Article Title: Performance of a Point-of-Care Fluorescence Immunoassay Test to Measure the Anti-Severe Acute Respiratory Syndrome Corona Virus 2 Spike, Receptor Binding Domain Antibody Level

doi: 10.3390/diagnostics13243686

Figure Lengend Snippet: Advantages and disadvantages of FastBio-RBD TM (fluorescence immunoassay) and GenScript-cPASS TM (SVNT).

Article Snippet: The correlation analysis showed that FastBio-RBD showed a very strong positive correlation to the Genscript SVNT, comparable with more sophisticated tests like the ECLIA and ELISA-based tests [ ].

Techniques: Fluorescence, Clinical Proteomics, Inhibition, Binding Assay, Neutralization, Comparison, Enzyme-linked Immunosorbent Assay

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Analytical performance of each kit in discriminating SARS-CoV-2 infection.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques: Infection

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Analytical performance for representativeness of neutralizing activity using the pre-defined cut-off values of each immunoassay kit.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques: Activity Assay

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Titer correlation of the analytical performance of the prediction of neutralizing activity using newly calculated cut-off values determined using Youden’s index.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques: Activity Assay

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Serial kinetics of antibody titers measured with each method: (A) PRNT ND50, (B.) GenScript cPass sVNT, (C) Roche Elecsys Anti-SARS-CoV-2, (D) Roche Elecsys Anti-SARS-CoV2 S, and (E) Abbott AdviseDx SARS-CoV2 IgG II.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques:

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Antibody titers by timeline.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques:

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Estimating the Neutralizing Effect and Titer Correlation of Semi-Quantitative Anti-SARS-CoV-2 Antibody Immunoassays

doi: 10.3389/fcimb.2022.822599

Figure Lengend Snippet: Scatter plot and Pearson’s correlation for each method grouped with acute/convalescent phase. (A) GenScript cPass sVNT, (B) Roche Elecsys Anti-SARS-CoV-2, (C) Roche Elecsys Anti-SARS-CoV2 S, and (D) Abbott AdviseDx SARS-CoV2 IgG II were compared with PRNT, respectively. Each colored line depicts the linear regression model and the surrounding grey-colored area represents the 95% confidence interval.

Article Snippet: ND 50 ≥ 20 , cPass sVNT , GenScript, RBD, total , 94.68% (91.51%–96.93%) , 81.32% (74.89%–86.70%) , 0.78.

Techniques:

Journal: medRxiv

Article Title: Function is more reliable than quantity to follow up the humoral response to the Receptor Binding Domain of SARS- CoV-2 Spike protein after natural infection or COVID-19 vaccination

doi: 10.1101/2021.06.02.21257975

Figure Lengend Snippet: Panel A shows the mean time of sample collection following natural infection (n=25) or after the first vaccine dose (n=20). In panel B and C, results from the total anti-Spike protein and the IgG titer measured by Enzyme-linked immunosorbent assay and expressed as OD or titers respectively are presented. The threshold for the total antibodies was 0.312 and the threshold for IgG titers was 1:100. All participants, except one, with previous exposure to SARS-CoV-2 showed detectable antibodies and measurable titers at baseline. Because the threshold 1:100 of our titration assay, the IgG titers at baseline in the unexposed subjects—which had no detectable S-specific antibodies—were set arbitrarily to 50. Panel D shows the blocking activity of serum antibodies expressed as percentage of neutralization by using a surrogate viral neutralization test (sVNT). The cutoff for this assay was 30%. As is shown, only one sample in the pre-exposed group contained antibodies below the threshold reported as more than 30% of neutralization. Also, while the distribution of antibodies and titers covers the full Y axis, values in both panel B and C, and in panel D same samples are grouped on the top values area. Two-way ANOVA multiple comparisons or unpaired T test analysis was used to test for increases or decreases among samples. P<0.05 was considered significant. Twenty-five participants (Natural infected) out of the 59 with the first sample collected between 12 and 39 days after the confirmed infection with SARS-CoV-2 were selected for comparison with the 21 unexposed-vaccinated subgroup (Healthy-vaccinated).

Article Snippet: To determine the neutralizing activity of antibodies we used a surrogate viral neutralization test (C-Pass GenScript sVNT, Piscataway NJ) ( , ).

Techniques: Infection, Enzyme-linked Immunosorbent Assay, Titration, Blocking Assay, Activity Assay, Neutralization, Comparison

Journal: medRxiv

Article Title: Function is more reliable than quantity to follow up the humoral response to the Receptor Binding Domain of SARS- CoV-2 Spike protein after natural infection or COVID-19 vaccination

doi: 10.1101/2021.06.02.21257975

Figure Lengend Snippet: Samples are described as 1st or 2nd samples after 1 st or 2 nd vaccine dose (1S-P1st-vd, 1S-P2nd-vd or 2S-P2nd-vd) and the mean time of samples collection is shown. Panels A and B show the total antibody and IgG titers, respectively, after full vaccination with two vaccine doses. Antibody levels and titers significantly decay in both groups in a second sample collected after the second vaccine (average of 60.3 and 100.5 days after the first vaccine dose for the unexposed and pre-exposed groups respectively). Despite the difference in sampling time between the two groups, there were no significant differences in the levels of antibodies or titers between groups in the 2S-P2nd-vd. Panel C shows antibody blocking capabilities measured by a surrogate viral neutralization assay (sVNT). Highly relevant is the finding that the blocking baseline activity of the pre-exposed individuals is significantly higher than the basely blocking activity induced by the first vaccine dose in unexposed individuals. In addition, two vaccine doses were necessary in the unexposed cohort to induce same percentage of neutralization achieved by just the first dose in the pre-exposed group. The magnitude of neutralization remained at similar levels until the last time point evaluated in both groups, confirming that the surrogate neutralization test is more suitable to determine the efficacy of the humoral immune response to the vaccine. The threshold for the total antibodies was 0.312. The threshold for IgG titers was 1:100 and for the blocking activity was 30%. Statistical significance was determined by two-way ANOVA multiple comparisons to test for increase or decrease among samples. p<0.05 was considered significant. The black arrows indicate the moment of vaccine administration related to the timing of sample collection. Healthy-vaccinated (n=21) Pre-exposed vaccinated (n=10).

Article Snippet: To determine the neutralizing activity of antibodies we used a surrogate viral neutralization test (C-Pass GenScript sVNT, Piscataway NJ) ( , ).

Techniques: Sampling, Blocking Assay, Neutralization, Activity Assay

Journal: Journal of Virological Methods

Article Title: Evaluation of a surrogate virus neutralization test for high-throughput serosurveillance of SARS-CoV-2

doi: 10.1016/j.jviromet.2021.114228

Figure Lengend Snippet: Sensitivity of the different serological tests and cut-offs used based on the final serum panels. Values between brackets represent 95 % confidence intervals on the estimations.

Article Snippet: Here, we performed an independent evaluation of a commercially available surrogate virus neutralization test (sVNT, GenScript cPassTM) that can be done without biosafety level 3 containment in less than 2 h. When using the cVNT and a Luminex multiplex immunoassay (MIA) as reference, the sVNT obtained a sensitivity of 94 % (CI 90–96 %) on a panel of 317 immune sera that were obtained from hospitalized and mild COVID-19 cases from Belgium and a sensitivity of 88 % (CI 81–93 %) on a panel of 184 healthcare workers from the Democratic Republic of Congo.

Techniques: Luminex

Journal: Journal of Virological Methods

Article Title: Evaluation of a surrogate virus neutralization test for high-throughput serosurveillance of SARS-CoV-2

doi: 10.1016/j.jviromet.2021.114228

Figure Lengend Snippet: Correlations between the percentage of inhibition measured by the surrogate viral neutralisation test (sVNT) and the log(dilution factors or signal-to-noise ratio) for the conventional viral neutralization test (cVNT) or the Luminex multiplex immunological assay (MIA) as calculated by the nonparametric Spearman correlation test (r s ). Seropositivity cut-off levels for the sVNT are indicated by the dashed grey lines at 20 or 30 % inhibition. Negative samples on the cVNT or MIA were not included in these figures.

Article Snippet: Here, we performed an independent evaluation of a commercially available surrogate virus neutralization test (sVNT, GenScript cPassTM) that can be done without biosafety level 3 containment in less than 2 h. When using the cVNT and a Luminex multiplex immunoassay (MIA) as reference, the sVNT obtained a sensitivity of 94 % (CI 90–96 %) on a panel of 317 immune sera that were obtained from hospitalized and mild COVID-19 cases from Belgium and a sensitivity of 88 % (CI 81–93 %) on a panel of 184 healthcare workers from the Democratic Republic of Congo.

Techniques: Inhibition, Neutralization, Luminex, Multiplex Assay

Journal: Nature

Article Title: Nanobodies from camelid mice and llamas neutralize SARS-CoV-2 variants

doi: 10.1038/s41586-021-03676-z

Figure Lengend Snippet: a , Table indicating (1) the total number of unique nanobody genes identified from llama and three nanomice phage display libraries following selection for RBD binding; (2) the number of nanobodies enriched at least tenfold after selection; (3) the number of nanobodies with a unique CRD3; and (4) the different clusters of nanobodies that share similar CDR3 s (with no more than 2 amino acid differences). b , Table showing in vitro neutralization results for the six leading nanobodies using the sVNT kit of GenScript. c , Dot plot depicting the extent of enrichment ( y axis) and frequency ( x axis) of unique nanobodies after RBD selection of llama (left) or nanomouse 1 (right) libraries. Green circles represent nanobodies that block ACE2–RBD interactions in vitro, black circles are nanobodies that do not efficiently block ACE2–RBD interactions, and grey dots represent untested nanobodies. d , Top graph shows protein alignment of the six nanobodies isolated from llama and nanomice immunized with SARS-CoV-2 spike and RBD. Bottom table shows detailed information of the VHH, D and J domains of nanomouse nanobodies. e , Table depicting equilibrium ( K D ), association ( K on ) and dissociation ( K off ) constants obtained for each nanobody as a monomer (black) or trimer (red) form.

Article Snippet: Extended Data Fig. 5 Isolation of anti-SARS-CoV-2 RBD nanobodies. a , Table indicating (1) the total number of unique nanobody genes identified from llama and three nanomice phage display libraries following selection for RBD binding; (2) the number of nanobodies enriched at least tenfold after selection; (3) the number of nanobodies with a unique CRD3; and (4) the different clusters of nanobodies that share similar CDR3 s (with no more than 2 amino acid differences). b , Table showing in vitro neutralization results for the six leading nanobodies using the sVNT kit of GenScript. c , Dot plot depicting the extent of enrichment ( y axis) and frequency ( x axis) of unique nanobodies after RBD selection of llama (left) or nanomouse 1 (right) libraries.

Techniques: Selection, Binding Assay, In Vitro, Neutralization, Blocking Assay, Isolation

Journal: iScience

Article Title: Biparatopic nanobodies targeting the receptor binding domain efficiently neutralize SARS-CoV-2

doi: 10.1016/j.isci.2022.105259

Figure Lengend Snippet: Characterization of nanobody RBD-binding (A) Bar graph showing the percentage inhibition of RBD binding to ACE2 for each nanobody (50 μg/mL) as measured by ELISA-based sVNT assay. Data points represent mean of 2 replicate wells from n = 3 independent experiments. (B) Flow cytometry histogram overlays showing nanobody or ACE2 tetramers binding to 293T cells transiently transfected to express full-length S protein or control T cell receptor (TCR) protein at their surface. (C) Top plots: surface plasmon resonance sensorgrams showing binding of soluble nanobody monomers to immobilized SARS-CoV-1 or SARS-CoV-2 RBD Fc dimers. Bottom plots: Saturation plots of nanobody binding to RBD-Fc proteins. Data points represent mean of n = 3 technical replicates. (D) Overlaid surface plasmon resonance sensorgrams showing ACE-2 or ACE-2/nanobody serial injections over immobilized SARS-CoV-2 RBD-Fc dimers. (E) Overlaid surface plasmon resonance sensorgrams of simultaneous nanobody injections over immobilized SARS-CoV-2 RBD-Fc dimers. (F) Bar graph of alanine scan data showing mean fluorescence intensity (MFI) of anti-IgG1 binding to RBD mutant-bound beads. Red data points for B1-Fc and G8-Fc are considered to have no binding. (G) Structural cartoon representation of the SARS-CoV-2 RBD binding to human ACE2 (PDB: 7KNI ( Zhou et al., 2020b )), highlighting residues identified in 2F.

Article Snippet: sVNT assay , Genscript , Cat#L00847-A.

Techniques: Binding Assay, Inhibition, Enzyme-linked Immunosorbent Assay, Flow Cytometry, Transfection, Control, SPR Assay, Fluorescence, Mutagenesis

Journal: iScience

Article Title: Biparatopic nanobodies targeting the receptor binding domain efficiently neutralize SARS-CoV-2

doi: 10.1016/j.isci.2022.105259

Figure Lengend Snippet: Biparatopic nanobodies negate escape by RBD variants of concern (A) Bar graph of variant array data showing MFI of anti-IgG1 binding to RBD variant-bound beads. Red data points for B1-Fc are considered to have no binding. (B) Bar graph of variant array data showing percentage inhibition of ACE2 binding to RBD variant-bound beads. Red data points are considered to have no binding, whereas orange data points have reduced binding. (C) A heatmap representation of the data in B. (D) Structural cartoon representation of the SARS-CoV-2 RBD binding to human ACE2 (PDB: 7KNI ( Zhou et al., 2020b )), highlighting residues identified in 2B-C. (E) A heatmap representation of neutralization titers from multiplex sVNT assay, testing neutralization of RBD-ACE2 binding using RBDs from a range of SARS-CoV-2 variants of concern and sarbecoviruses. (F) Schematic of mouse challenge model. (G and H) Bar graphs showing G. viral TCID or H. PCR values from lungs of mice challenged with SARS-CoV-2 after treatment with nanobody proteins. See also Figure S4 and Table S1 .

Article Snippet: sVNT assay , Genscript , Cat#L00847-A.

Techniques: Variant Assay, Binding Assay, Inhibition, Neutralization, Multiplex Assay

Journal: iScience

Article Title: Biparatopic nanobodies targeting the receptor binding domain efficiently neutralize SARS-CoV-2

doi: 10.1016/j.isci.2022.105259

Figure Lengend Snippet:

Article Snippet: sVNT assay , Genscript , Cat#L00847-A.

Techniques: Virus, Recombinant, Plasmid Preparation, Transfection, Extraction, Binding Assay, Expressing, Software, Luminex, Microscopy