surrogate viral neutralization test (svnt, c-pass)  (GenScript corporation)

Journal: Antibody Therapeutics

Article Title: Design of a chimeric ACE-2/Fc-silent fusion protein with ultrahigh affinity and neutralizing capacity for SARS-CoV-2 variants

doi: 10.1093/abt/tbad001

Figure Lengend Snippet: Paradigm’s ACE-2 variant LVE/STR chimera neutralizes Beta Variant B.1.351 RBD significantly better than w.t. SARS-CoV-2 RBD. sVNT assays were performed with SARS-CoV-2 RBD proteins expressing the Beta Variant B.1.351 sequence (K417N, E484K and N501Y mutants, red bars) or the w.t. (original Wuhan strain) sequence (blue bars) incubated with the ACE-2 LiVE/STR construct. Dilutions shown are 0.05–2.4 ng/ml, left to right. Note sVNT titers of ~ 2.4 ng/ml for neutralization of the SARS-2 Beta variant.

Article Snippet: The surrogate Viral Neutralization Test (sVNT, C-PASS, GenScript USA Inc., Piscataway, NJ 08854) was used to characterize the antibodies described, using the methodology defined previously [ ].

Techniques: Variant Assay, Expressing, Sequencing, Incubation, Construct, Neutralization

Journal: Antibody Therapeutics

Article Title: Design of a chimeric ACE-2/Fc-silent fusion protein with ultrahigh affinity and neutralizing capacity for SARS-CoV-2 variants

doi: 10.1093/abt/tbad001

Figure Lengend Snippet: Paradigm’s ACE-2 variant LVE/STR chimera neutralizes Alpha Variant B.1.1.7 RBD significantly better than GenScript IgG FL18–740 w.t. ACE-2 mAB. sVNT assays were performed with SARS-CoV-2 RBD proteins expressing the Alpha Variant B.1.1.7 sequence (N501Y mutant) challenged with either Paradigm’s ACE-2 variant LVE/STR chimera (dark blue bars) or with the GenScript IgG FL18–740 w.t. ACE-2 mAB (light blue bars, binding affinity 3 nM). Dilutions shown are 0.05–2.4 ng/ml, left to right. Note sVNT titers of ~ 6.3 μg/ml for the Genscript mAB for neutralization of the Alpha variant, in contrast to ~ 4.9 ng/ml for neutralization of the Alpha variant by the Paradigm construct LiVE-STR.

Article Snippet: The surrogate Viral Neutralization Test (sVNT, C-PASS, GenScript USA Inc., Piscataway, NJ 08854) was used to characterize the antibodies described, using the methodology defined previously [ ].

Techniques: Variant Assay, Expressing, Sequencing, Mutagenesis, Binding Assay, Neutralization, Construct

Journal: Antibody Therapeutics

Article Title: Design of a chimeric ACE-2/Fc-silent fusion protein with ultrahigh affinity and neutralizing capacity for SARS-CoV-2 variants

doi: 10.1093/abt/tbad001

Figure Lengend Snippet: Paradigm’s ACE-2 variant LVE/STR chimeras potently neutralize the SARS-CoV-2 Omicron Variant B.1.1.529. sVNT assays were performed with purified recombinant SARS-CoV-2 RBD (top panel) or spike protein trimers (bottom panel) expressing the Omicron variant sequences described in . The bargraphs show inhibition of the binding of Omicron RBD (top) or Omicron spike protein trimer (bottom) to purified recombinant ACE-2 by either Paradigm’s “LiVE” ACE-2 variant LVE/STR STR Fusion protein chimera or by the “LiVE Longer” LVE/STR STR–YTE IgG chimera. Dilutions shown are 0.05–2.4 ng/ml, left to right. Note similar sVNT titers of ~ 4.9 ng/ml for neutralization of Omicron RBD or Omicron spike trimers, and slightly better neutralization by the “LiVE Longer” chimera (green). See ( and ) for additional details about the ACE-2/Fusion protein chimeras.

Article Snippet: The surrogate Viral Neutralization Test (sVNT, C-PASS, GenScript USA Inc., Piscataway, NJ 08854) was used to characterize the antibodies described, using the methodology defined previously [ ].

Techniques: Variant Assay, Purification, Recombinant, Expressing, Inhibition, Binding Assay, Neutralization

Journal: Viruses

Article Title: Limited Impact of Delta Variant’s Mutations on the Effectiveness of Neutralization Conferred by Natural Infection or COVID-19 Vaccines in a Latino Population

doi: 10.3390/v13122405

Figure Lengend Snippet: Neutralization capacity of sera from infected and non-infected individuals against SARS-CoV-2 variants before and after vaccination. The neutralization activity of sera from infected individuals ( n = 10) and non-infected ones ( n = 21) before and after vaccination was evaluated against the six variants of concern. Dotted lines indicate the limit of detection of the sVNT assay, where the percentage of signal inhibition is determined (≥30% indicates a positive result). A normality test (Shapiro–Wilk) was performed for all datasets in order to assess the distribution of the data. The significance threshold for all analyses was set at p < 0.05. ( A ). Neutralization activity of sera from infected individuals ( n = 10) before vaccination. A one-way ANOVA test with Dunnett’s multiple comparisons test was performed between each of the variants. ( B ). Neutralization activity of sera from healthy individuals ( n = 21) after receiving the 1st vaccine dose. A one-way ANOVA test with Dunn’s Kruskal–Wallis multiple comparisons test was performed between each of the variants. ( C ). Neutralization activity of sera from infected individuals ( n = 10) after receiving the first vaccine dose. A one-way ANOVA test with Dunnett’s multiple comparisons test was performed between each of the variants. ( D ). Neutralization activity of sera from healthy individuals ( n = 21) after receiving the 2nd vaccine dose. A one-way ANOVA test with Dunn’s Kruskal–Wallis multiple comparisons test was performed between each of the variants. ( E ). Neutralization activity of sera from infected individuals ( n = 10) after receiving the 2nd vaccine dose. A one-way ANOVA test with Dunnett’s multiple comparisons test was performed between each of the variants. ( F ). Neutralization activity of sera from vaccinated individuals, pre-exposed ( n = 10, depicted in circles) and healthy ( n = 21, depicted in squares), after receiving the 2nd dose was evaluated. A one-way ANOVA test with Dunn’s Kruskal–Wallis multiple comparisons test was performed between each of the variants.

Article Snippet: To determine the neutralizing activity of antibodies against SARS-CoV-2, we used a surrogate viral neutralization test (C-Pass GenScript sVNT, Piscataway, NJ, USA) according to the manufacturer’s instructions [ , , ].

Techniques: Neutralization, Infection, Activity Assay, Inhibition